DE3001061A1 - GAS WAREHOUSE - Google Patents

Description

GEYER, HAGEMANN & PARTNER

PATENT LAWYERS 3ΌΌ '06!

Destoufhcsstraßi »60 · Postfach 400745 · 8000 Munich 40 -Telex 5-216136 h, ij> e d · 7ol (>>; ranim hjgeyp.itent -Teleknpierer 089'JO4071

u.z .: Pat 129 / 3-79M Munich, January 12th, 1980

Dr.G / 2 / he

NIPPON TELEGRAPH & TELEPHONE PUBLIC CORPORATION

Tokyo / Japan

GAS STORAGE

Claimed priorities:

Country: Date: Case number:

Japan January 13, 1979 3202/1979 Japan July 3, 1979 91516/1979 (GBM registration)

030029/0892

GEYER, HACEMANN & PARTNER

Destouc hesslr.iße 60 ■ Postfach 400745 · 80 (K) Munich 40 ■ Telephone 089/1040 7V -Telex 5-216136 Ιι, ΐβρ d ■ Telegram hagi-ypdlfnt · Fax machine O89'3O4O71

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Nippon Telegraph & Telephone Munich, the

Public Corporation .. - ^ -, ^ _0n

* January 12, 1980

Tokyo / Japan

u.z .: Pat 129 / 3-79M Dr.G / 2 / he

GASLAGEK

The invention relates to gas bearings, in particular to hydrostatic and so-called "hybrid" gas bearings, in which the hydrostatic and the hydrodynamic effect are used and in which to support a rotatable shaft (radial bearing) or to support a support part (axial bearing) gas under pressure from a Pressurized gas source can each be fed to a bearing gap between a bearing shell of the bearing and the one to be supported Part (shaft, support part) is formed.

Such bearings have proven to be indispensable, e.g. for high-speed operations in large storage facilities Rotary head recording devices are used. The use of this rotary head recorder is opposite that of known fixed head magnetic tape recorders more advantageous, because a rotary head recorder with much higher Recording density can work and at the same time too the dimensions of this recorder are smaller. On the other hand, it is disadvantageous in rotary head recorders that their data flow rate is low and their sequential access time is long. The reason for this lies that the speed of rotation is currently available

030029/0892

ble rotary heads is 5600 revolutions per minute (rpm) and the head scanning speed is low, for example 25.4 m / s. Increasing the rotation speed to about 15,000 rpm and the head scanning speed
at around 50 m / s could be a solution to these problems
bring. On the other hand, it has been shown that increasing the speed above 10,000 rpm using conventional ball bearings is not possible because of their lack of reliability or operational safety, which is why it has proven to be fundamentally important to use air bearings for this purpose.

Rotary head recorders that use compressed air as
hydrostatic and / or hydrodynamic bearings are now used for video tape recorders in broadcasting

and television area. However, the use of a hydrostatic pressure gas bearing requires the use of a reciprocating compressor, so that it is difficult to use such a device in computer peripherals adapt. In hydrodynamic pressurized gas bearings, difficulties arise from the fact that the rotatable shaft

and the bearing shell are in contact with one another before the bearing starts up: such a bearing then does not have
the desired operational reliability when it is used in a rotary head recorder for electronic computers.

is set, which is required that they
for many years without maintenance or even repairs one-i? have to be tough. It has therefore proven to be
proved desirable, so-called "hybrid" gas storage
to develop in which the shaft to be supported by

hydrostatic pressure in the start and run-out phase
of the bearing is supported while rotating
the support is provided by hydrodynamic pressure.
Such bearings can work with high efficiency using pressurized gas of a pressure of about 0.08 kg / cm ² , the pressurized gas of a conventional one

Blower can be provided. That way is

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it possible to use a high speed rotary head recorder great operational safety and high operational reliability to provide direct body contact during the start-up and braking phase is avoided between the bearing shell and the part to be supported.

So far, for the use of a hydrostatic gas bearing of the type with a self-throttling effect ("inherent throttling") - as already mentioned - it has been necessary to use a reciprocating compressor, since the so-called " ^{bearing efficiency 11"} (ie the ratio between the support pressure available in the bearing for the shaft and the pressure of the supplied compressed gas) is only low, ie at most about 50%. Since the optimal value for the bearing gap or the bearing clearance is still relatively large, the overall bearing rigidity is only low (bearing effectiveness / bearing clearance) It thus proved impossible to reduce the optimal bearing clearance below 10 μm without a noticeable decrease in bearing effectiveness at the same time. For this reason, not only was it not possible to achieve a sufficiently high bearing rigidity for bearings of this type, but also sufficient utilization the hydrodynamic effect, which occurs with narrow bearing play and sets high rotational speed and its effective utilization for the use of such a bearing as a hybrid gas bearing would be required.

In order to create at least a certain improvement compared to this type of bearing, it was used as a different type of bearing proposed a gas bearing with a surface-dependent throttle effect, in which the optimal bearing play can be reduced to less than 10 μm and in which a bearing pressure to support the bearing load is effectively present and available in an area that extends to the ends of the bearing approaches. In this way, with increased storage

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stiffness achieve a storage efficiency that was substantially equal to that of the other type of bearing. However, it turned out that these gas bearings had to be provided with a large number of axial longitudinal grooves are difficult to create, and they also have an effect axial longitudinal grooves a non-uniformity of the bearing surface in the direction of the relative movement, which is an effective use of the hydrodynamic effect caused by the rotation of the shaft can be achieved is prevented, so that this type of bearing cannot be used as a hybrid gas bearing either is.

Based on this, the invention is essentially based on the object of an improved gas pressure bearing with high To create bearing effectiveness and high bearing rigidity that is easy to manufacture as a hybrid gas bearing of high effectiveness can be used and operated with compressed gas of relatively low pressure.

According to the invention, this object is achieved in a gas storage facility, in the case of the underpressure of gas from a pressurized gas source to support a rotatable shaft between a bearing gap a bearing shell and the shaft can be fed, achieved in that the bearing shell has several in its circumferential direction having extending annular grooves which extend along the entire inner bearing surface, axially to one another offset and are open to the bearing gap, that still a plurality of offset at an angle to each other arranged air supply ducts of small diameter are provided, each with associated annular grooves in Are connected, and that a gas passage is provided for connecting the gas supply channels to the pressurized gas source.

The measure according to the invention creates a pressurized gas bearing created, in which both the hydrostatic and the hydrodynamic effect for supporting the

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Pat 129 / 3-79M ÖJUUiü / Uöy ^

Storage can be used effectively and that a high storage efficiency, has great bearing rigidity and easy manufacturability. According to the invention thus created a very effective hybrid gas storage facility both during the start-up phase as well as during During the run-out phase of the bearing, the rotating shaft to be supported runs without contact within the bearing bush. At the Gas storage according to the invention, the use of gas, preferably air, relatively low pressure is possible Can easily be provided by a small rotary compressor, which in turn over a long Operating time without maintenance, relubrication, etc., which results in a correspondingly long maintenance-free Operating time for the warehouse results. The support of the shaft or the shaft collar running in the bearing housing can, when the start-up phase has ended, take full advantage of the hydrodynamic effect, which is achievable by the high speed rotation of the shaft. The camp according to the invention has a simple structure and can be used with a particularly small bearing clearance of only a few μΐη, what turns out to be a particularly great advantage. Because of this, the bearing according to the invention can be considered a special View less complex hydrostatic gas bearing with a large load capacity and high rigidity. Besides In the case of the bearing according to the invention, the bearing surface is so smooth that there is an effective hydrodynamic Pressure can build up as soon as the shaft rotates. The invention thus provides a compact and operationally reliable one Hybrid gas bearing achieved in which in the start-up and run-down phase a contact between the relative to each other moving bearing parts is completely avoided and that at high speeds, e.g. in one Range from 10,000 to 30,000 rpm, is effective as a hydrodynamic bearing, with pressurized gas of only low pressure used by a rotary compressor without the need for relubrication for a long period of time

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can be. Compared to the previously known hydrostatic gas bearings with a self-throttling effect (inherent Throttling) is when using the bearing according to the invention an improvement in bearing capacity of 30 up to 40% and the bearing stiffness more than 5 times possible. If you also choose the number of air supply channels low and if a small bearing clearance is used, then it is possible to use the required amount of pressurized gas to less than 1/10 of the amount in the case of previously known bearings was required to reduce. The invention enables the creation of a hybrid gas bearing of high efficiency, as was previously not possible when using conventional hydrostatic gas bearings. Since the ring grooves that are used in the camp according to the invention, easily can be manufactured and processed, the manufacturing costs of the bearing according to the invention are only of an order of magnitude which corresponds to the simplest common hydrostatic gas bearing. While the camp according to the invention the required amount of pressurized gas is essentially the same as it is in a hydrostatic gas bearing with surface-related Throttle effect is required, in contrast, is the load-bearing capacity in the bearing according to the invention and the bearing rigidity but more than 1.5 times better and the processing or manufacturing costs drop to a fraction of the cost of these previously known bearings.

In an advantageous embodiment of the gas bearing according to the invention each annular groove is spaced from one end of the bearing a distance that is about 5 to 15% of the total Stock length corresponds. The depth of the ring grooves is preferably 1.5 to 6 times the bearing play. It is also advantageous if the gas supply ducts are spaced essentially the same distance from one another in the circumferential direction are offset. There is a further advantageous embodiment of the gas bearing according to the invention also-in the fact that a multitude of diagonally to the wave-

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4 *

Axial grooves are attached in a herringbone pattern on the surface of the shaft collar, creating When the shaft rotates rapidly, additional gas (air) from outside the bearing into the bearing to support the hydrodynamic pressure build-up can move in there.

Another advantageous embodiment of the gas bearing according to the invention is that at least one the inner bearing surface is provided in the bearing shell in separate individual surfaces dividing the annular groove with a radial outlet is in communication, and that further annular grooves near the first-mentioned, dividing the bearing surface Annular groove with a plurality of gas supply channels are provided, these gas supply channels from the inside the bearing shell open out into the respectively assigned annular groove. This training is then an advantage if the length of the bearing shell is greater than that of the bearing diameter or if the number of compressed gas feeds is large because then the flow resistance in the axial direction of the bearing increases to a value which are no longer neglected in comparison to the flow resistance in the circumferential direction of the bearing can, whereby the gas pressure then decreases in the high pressure area of the bearing and increases in the low pressure area of the bearing (See. Representations according to FIG. 11 of the drawing). As a result, the pressurized fluid under such conditions is deflected somewhat in the circumferential direction in the high-pressure area of the bearing and thus enters the low-pressure area of the Camp, which results in a pressure distribution that is not advantageous for the function of the camp. These Problems arise with the advantageous embodiment of the bearing according to the invention described above prevented by dividing the storage area into individual storage areas, the effective storage length in each case reduced in size, which then improves the desired pressure distribution in the camp and thus improves it the storage effectiveness occurs. It is advisable to

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to select the axial distance between the air supply ducts within the individual surfaces so that it corresponds to a length of 2/3 to 1/2 of the respective storage length. If it becomes smaller than half the effective bearing length selected, an improvement in storage efficiency can no longer be achieved as a result. if it what is desired is the radial load-bearing capacity of the bearing by increasing the length of the radial bearing / then it is recommended / the surface of the Split the bearing shell into three or four individual sections by arranging two or three dividing grooves. In this case, two annular grooves with associated gas supply channels would then advantageously be used for each bearing section for blowing in the compressed air.

Advantageously, in an inventive Gas bearings also provided a plurality of axial grooves which connect the annular grooves to one another and their Depth is made smaller than that of the annular grooves.

Another gas bearing according to the invention is based on a gas bearing, in which one is used for supporting storage Support part of gas under pressure from a pressurized gas source a bearing gap between a in the form of a round Plate formed bearing washer of a thrust bearing and the support part to be mounted can be fed. According to the invention the bearing disk with a central opening and one of the two bearing surfaces (on the bearing disk or on the support part) with several concentrically arranged circular grooves open towards the bearing gap, its innermost near the central opening and its outermost near the outer boundary the bearing washer is attached. Furthermore is a multitude of small diameter gas supply channels arranged offset from one another in the circumferential direction of the circular groove

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provided / which are each connected to an associated circular groove and via suitable gas lines (Gas passages in the bearing shell) are connected to the compressed air source. It is an advantage if the innermost circular groove from the central opening and the outermost circular groove from the outer circumference of the bearing washer, respectively have a distance that corresponds to about 5 to 15% of the size of the bearing diameter. Preferably is the depth of the circular grooves about 1.5 to 6 times the value of the bearing gap. Particularly balanced Pressure conditions can be achieved in the gas pressure cushion used for storage in that the gas supply channels mounted offset from one another in the circumferential direction of the bearing disk at essentially the same distance are.

This type of bearing according to the invention accomplishes that Principle of the invention on a thrust bearing.

Another inventive gas bearing is based on a Gas bearing in which a rotatable shaft is used for training axial and radial bearing support surfaces is provided with a section narrowed in diameter, which is used for Receiving an externally engaging bearing shell is used, with gas under pressure from a pressurized gas source radially and axially extending bearing gaps is supplied, each between the bearing surfaces of the bearing shell and the individual support surfaces of the shaft collar narrowed in diameter are formed: this gas bearing is a at the same time effective as radial and axial bearings Gas storage. According to the invention, this has as a radial bearing trained bearing part for radially effective storage on a radial bearing surface and several in Circumferentially extending annular grooves along the entire inner circumferential surface of the radial bearing surface run near the bearing ends and axially offset from one another and are open to the radial bearing gap, and

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Pat 129 / 3-79M

also a large number of offset from one another at an angle Small diameter gas supply channels for each annular groove, the gas supply channels each with their associated annular grooves are in communication, and also a gas passage for connecting the gas supply channels with the pressurized gas source. According to the invention, the bearing part, which is used as the axial bearing, also has in this bearing serves, axial bearing surfaces each with several circular grooves open to the respective axial bearing gap, its innermost near the radial bearing surface and its outermost near the non-narrowed radial outer circumference the rotatable shaft, as well as a large number of gas supply channels of small diameter for the annular grooves on, wherein the gas supply channels are each with the associated circular groove in connection to this with to connect the gas passage. According to the invention, connecting lines are also at the same time between the radial bearing surface and the axial bearing surfaces are provided, which are in communication with the environment via outlets running through the shaft. The invention is realized in this camp in the form of a simultaneous axial and radial bearing.

Such a gas storage facility is more advantageous for the reasons already mentioned earlier in another place in the event that the bearing length is greater than the Bearing diameter and / or the number of air supply channels is very large, at least one annular groove is provided which divides the inner bearing surface of the radial bearing into separate bearing surfaces and connected to a radial outlet is; furthermore, additional circumferential annular grooves are arranged near this dividing groove, and there are also a large number associated with these further circumferential annular grooves and opening into the respectively associated annular groove Gas supply channels provided.

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Pat 129 / 3-79M Q3Q029 / 0892

Another gas storage facility that continues as well as the others The gas bearing described above solves the problem underlying the invention, consists in a gas bearing that is designed as a radial bearing and in the case of the gas under pressure from a pressurized gas source into. A bearing gap can be introduced between a bearing shell and a rotatable shaft to support it during rotation. According to the invention the bearing shell is hereby arranged with a large number of offset from one another at an angle Provide gas supply channels of small diameter, which are open to the bearing gap, (i.e. open into the bearing gap) and are near the two ends of the camp; there is also a connection for the supply of pressurized gas provided from the compressed gas source to these gas supply channels, and on the rotatable shaft are several circumferential Annular grooves attached, each at points that are opposite the mouths of the gas supply channels, are provided on the shaft and are open to the bearing gap.

Another gas bearing embodying the invention is based on a gas bearing, which is designed as a thrust bearing and in which gas from a pressurized gas source is below Pressure can be introduced into the bearing gap between a bearing surface and a rotatable shaft collar to support it is. According to the invention, the rotatable shaft (preferably formed in one piece with it) has axial On bearing plates which are opposite the two opposite axial end surfaces of the bearing shell, each of the bearing plates having a plurality of concentrically arranged, open toward the bearing gap Circular grooves are provided, the innermost close to the inner circumferential surface of the bearing and the outer close to the outer circumference the axial bearing plate is attached; Furthermore, the bearing shell with several concentrically arranged, axially, however, provided only briefly formed gas supply channels, which towards the respective bearing gap

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are open, opposite the concentric circular grooves of the shaft, arranged offset from one another at an angle and are connected to the pressurized gas source via a gas line. In contrast to those described above Bearing forms according to the invention in which the annular grooves are always attached to the bearing shell were, in this gas bearing according to the invention, the arrangement of the annular grooves on the in the bearing shell bearing shaft or the shaft collar rotating there.

All bearings according to the invention described above solve the problem on which the invention is based, each being simply constructed, light and therefore inexpensive manufacturable, fully effective hybrid gas bearings are created that are reliable over a long period of time can be used and where compressed air is only relatively low pressure from a conventional Rotary compressor can be used.

In the following, the invention is explained in more detail in principle by way of example with reference to the drawing. Show it:

1 shows a partially sectioned perspective view of an example of a hydrostatic gas bearing with a self-throttling effect from the prior art;
2 shows a partially sectioned perspective view of an example of a hydrostatic gas bearing with a surface-dependent throttle effect from the prior art;

Fig. 3 is a graphical representation of the dependence of the bearing effectiveness on the bearing clearance in a hydrostatic gas bearing with self-throttling effect from the prior art according to FIG. 1;

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4 shows a longitudinal section through an exemplary embodiment a bearing according to the invention;

FIG. 5 shows a cross section through the bearing according to FIG. 4;

6 shows a graphic representation of the dependency of the bearing efficiency on the bearing clearance in the exemplary embodiment according to FIG. 4, the depth of the annular grooves being selected as a parameter for the various curves;

7 is a graph showing the dependency of the bearing efficiency on the bearing clearance in the example according to Fig. 4, the ratio of the distance in the bearing housing for the various curves provided feed end ring grooves from the end of the bearing surface to the entire bearing length as a parameter is chosen;

Fig. 8 is a graphic representation of the radial pressure distribution on the bearing surface, wherein for the various curves, the depth of the annular grooves is used as a parameter; 9 shows a longitudinal section through a second embodiment of a bearing according to the invention;

10a shows a sectional view through a further embodiment a bearing according to the invention;

Fig.10b is a plan view of the lower bearing plate of the Arrangement from FIG. 10a;

11 shows a representation of the pressure distribution characteristic in the axial direction on the inside of the bearing;

12 shows a longitudinal section through a further embodiment of a bearing according to the invention; 13 shows a cross-sectional representation (partial section) through air supply ducts lying in a radial plane of the radial bearing according to FIG. 12;

14 shows a cross-sectional view from FIG. 12 with a View of the guide surface of the bearing; 15 shows a longitudinal section through a section of a further embodiment of a bearing according to the invention, and

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16 shows a longitudinal section through a further embodiment for a bearing according to the invention.

In the interest of a better understanding of the invention, an example should first be given in FIGS. 1 and 2 for a bearing from the prior art are shown, an example being a known bearing with a self-throttling effect (Fig. 1) and an example of a previously known bearing with a through the design of the bearing surface conditional throttle effect can be shown.

In the hydrostatic gas bearing 2 with self-throttling effect shown in FIG. 1, there is a plurality of air supply bores 3 provided / which open towards the bearing surface and to each other in the circumferential direction and in the axial direction are offset. Furthermore, a common air supply channel 5 is in connection with the air supply bores 3 is provided, which is supplied with compressed air from a compressor (not shown in the figure) will. The bearing is designed to support a shaft in a bearing. The openings of the air supply holes 3 can each at the point where they face the shaft 1, something to form flat pockets, preferably conical, flared, thereby forming a throttling type bearing.

Although gas bearings with self-throttling effect or with orifice throttling ^ can be easily manufactured and processed, the value for the "storage effectiveness" (ratio the pressure available to support the bearing compared to that of the compressed air supplied) at a maximum of 50%. and In addition, the "bearing rigidity" is low, since the optimal bearing clearance of such a bearing is relatively large.

Fig. 3 shows the course of the storage efficiency over the Bearing play of the bearings described above. In general, it can be seen that the optimal bearing play in which

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the storage efficiency reaches its maximum, relatively large is, e.g. 20 to 30 μπι or above, and that with a small bearing clearance of less than 10 μΐη the load capacity of the camp drops to a great extent. The value for the optimal bearing clearance can be reduced by the diameter of the air supply holes and their number is reduced, whereby the throttling effect (namely the Flow resistance for the gas) of the air supply holes increases. With known processing techniques can However, only achieve a minimum diameter of the air supply holes of 0.08 to 0.1 mm, so that it can proves impossible, the optimal bearing clearance below 10 µm without losing storage effectiveness, since the • storage effectiveness drops when the number of air supply holes is below 6. Because of this, it has proven impossible with bearings of this type, not just in to raise the bearing rigidity sufficiently, but also to fully support the shaft shaft To be able to take advantage of the hydrodynamic effect in a narrow bearing clearance in a high-speed rotation is produced.

In order to at least partially eliminate the disadvantages of the bearing types with self-throttling effect and those with orifice throttling to be able to, the bearing type shown in Fig. 2 with surface-related throttle defect was developed at which reduces the optimal bearing clearance to less than 10 and at which the effective bearing pressure to absorb the bearing load up to the ends of the bearing is available is. This allowed essentially the same storage effectiveness as the bearings mentioned above Species, but at the same time a higher bearing rigidity can be achieved. In the illustration according to FIG. 2, a bearing with a surface design conditional throttling effect a plurality of extending in the longitudinal direction of the shaft and around the circumference of the shaft arranged grooves 4 distributed on the

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Shaft or the shaft collar 1 ¹ attached, except at the points of the shaft collar which are opposite the two opposite ends of the bearing surface of a bearing 2 '. Since this type of bearing must be provided with a large number of longitudinal grooves, it is difficult to manufacture and machine. In addition, the hydrodynamic effect that is generated by the rotation of the shaft collar I ¹ is not used effectively. In particular, there is no continuous bearing play in the circumferential direction, but it is split up by the large number of longitudinal grooves 4 and the compressed air in the bearing also has the tendency to escape through these grooves to the outside, so that the hydrodynamic effect is significantly less than with a bearing which is not provided with such longitudinal grooves.

The invention will now be compared with these known bearings on the basis of the further figures.

4 and 5, a shaft 11, a bearing 12 and narrow circular grooves 13 are shown, which extend in a circle and each form a closed circular groove in the bearing surface. The annular grooves 13 are each on Places arranged from the corresponding, opposite bearing ends at a distance L. away are, which in turn makes up about 5 to 15% of the total length L of the bearing. Each groove has a depth g one Size of about 1.5 to 6 times the bearing clearance. Furthermore, air supply bores 14 are of small diameter provided, which are open towards the radial grooves and connected to a compressed air source 16 via an air chamber 15 are. The number of air supply channels or openings is selected so that it is smaller than that of the known Gas storage. The compressed air supplied by the compressed air source 16 flows into the narrow annular grooves 13 with the interposition of the air chamber 15 and

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ZH

of the air supply ducts 14. The compressed air supplied in this way flows through the grooves 13 in the circumferential direction of the bearing and then outwards through the bearing play. The diameter of the air supply ducts is advantageously made as small as possible, for example less than 0.1 mm, and their number is chosen to be three or four. In the form shown in FIG. 5, three air supply ducts 14 are used, which are arranged at an angle to one another at substantially the same angular intervals.
10

The optimum operating point of the hydrostatic bearing is reached when the flow resistance R. of a passage from the air chamber 15 to the bearing surface via the air supply channels 14 and the narrow feed grooves equals the flow resistance R of a passage in the bearing clearance between the lateral edges of the grooves and the bearing ends . The flow resistance R- is inversely proportional to the square of the diameter d of the openings of the air supply ducts 14 and their number, whereas the flow resistance R "is inversely proportional to the three-fold power of the bearing play Cr (which is exaggerated in FIG. 5 to show an eccentric position of the shaft collar 11 shown) and is proportional to the outflow length L. The outflow length L ₁ , the diameter d of the air supply ducts 14 and their number are chosen to be as small as possible in order to meet a condition R ₁ ^ R "for a smaller bearing clearance Cr. As described above, according to the invention the outflow length L _{1 is} selected to be small in order to limit the outflow resistance, and the number of air supply ducts 14 is reduced in order to increase the resistance to the air flow, whereby the inflow resistance (R.) and the outflow resistance (R " ) become the same size to achieve the optimal operating condition.

In Figs. 6 and 7, the course of the bearing effectiveness and the bearing clearance Cr for a diameter of the air

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supply channels of 0.1 mm for a number of three air supply channels as well as for a ratio of the bearing length to the bearing diameter (L / D: cf. representations from FIG. 4) = 1. In particular, FIG. 6 shows the course of the bearing effectiveness over the bearing play for the values L ₁ ZL = 0.05 and for a pressure of the supplied compressed air of 1 kg / cm ² , the groove depth g of the annular grooves 13 as a parameter for the various curves is chosen. The optimum depth of the annular grooves 13 is approximately 4 times the value of the bearing clearance Cr, while the optimum clearance is about 7 [in the value at which a bearing efficiency can be achieved of about 0.7. Even if the depth of the annular groove 13 and the position clearance are slightly different from their optimal values, the bearing efficiency still does not decrease to a noticeable extent. If the L / D ratio is lowered to values of 2/3 and 1/2, then the maximum storage efficiency increases to 0.8 and 0.85, respectively. Depending on the pressure of the compressed air supplied, the optimum bearing play fluctuates somewhat, e.g. for values of the air pressure of the compressed air supplied of 5 kg / cm ² and 0.1 kg / cm ² , the optimum bearing play is approx. 5 or 9 μπι.

7 shows the course of the curve of the dependence of the bearing effectiveness on the bearing clearance Cr for the case of an output ^{pressure of 0.1 kg / cm 2} for the compressed air supplied, for a diameter of 0.1 mm for the air supply ducts and for the ratio L, / L shown as a parameter. It can be stated that a change in the value of the ratio L ../ L also causes a change in the optimum depth for the annular grooves in order to maximize the value for the bearing efficiency. From Fig. 7 it can be seen that L ₁ ZL should be chosen to be less than 0.1 in order to reduce the bearing clearance below 10 microns. However, it should be noted that the value of L ^ L that this

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BATH ORIGINAL

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Condition met, increases when the output pressure of the supplied Compressed air is increased and the diameter of the air supply ducts is reduced.

For a better understanding of the presence of an optimal Ringnuttiefe, wherein the bearing efficiency is at a maximum to the dependence of the circumferential pressure distribution of the bearing can be investigated by the groove depth: in Figure 8 is for this purpose, the dependence of the pressure on the bearing shell periphery (of as a developed ümfangswinkel ψ. is shown), which is generated by the eccentricity of the shaft collar 11, shown by the depth g of the circumferential annular groove 13, the width of the annular groove being 1 mm and the number of air supply channels being three. In the illustration of FIG. 8, P denotes the outlet pressure of the supplied compressed gas, MAXiCr denotes the maximum bearing gap width that occurs (bearing clearance at Kp = 0 °) and MINiCr denotes the minimum bearing gap width that occurs (min.bearing clearance at u> = 180 °). As can be seen from the illustration in FIG. 8, in the case of very large groove depths g, the short-circuiting effect (equalizing effect) between the pressures in the area of the bearing, where there is a large bearing clearance due to the eccentricity, and the bearing area, where due to the Eccentricity a tighter bearing play occurs, too, ie the pressure difference between the angular range -90 ° <^ <90 ° and the range 90 ° <y? <270 ° decreases so much that the load-bearing capacity of the bearing drops. For this reason, there is an optimal value for the groove depth g of the annular grooves at which the bearing efficiency is maximum.
The bearing clearance (bearing gap width) is designated with Cr, the bearing diameter with D, the number of air supply channels with n, the width of the ring groove with b and the distance between the outer side of the ring groove closest to the bearing end and this bearing end with L., then the optimal groove depth g can be determined approximately by the following equation:

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ORIGINAL BATHROOM

a er [{(^ -y ² / b ^ J - I].

From this, for example, a ratio g / Cr SS 3 can be calculated if D = 28 mm, η = 3, b = 1 mm and L ₁ = 3 mm. In general, the value for the ratio g / Cr is in a range from about 1.5 to 6. If the air supply bores and the annular grooves are shifted even further towards the bearing ends, the bearing efficiency increases and the optimal bearing clearance decreases. However, if the lengths of the outflow L. are too small, would inaccuracies or errors result in the arrangement or in the assembly so strong fluctuations in the storage characteristics in that the length L ₁ should be at least mm. 1 Therefore, the air supply ducts 14 should be attached at such locations that are about 5-15% of the total bearing length away from the corresponding bearing ends.

If one chooses, for example, a diameter of 30 mm for the shaft collar, an effective bearing length of 50 mm and a pressure for the supplied air of about 0.07 kg / cm ² , then it is possible with a bearing according to the invention to produce a Load of 700 g to be absorbed or supported by the optimal design of the bearing. If a bearing of this design is used for a rotating rotary head recording device, then this can be carried out with a weight of less than 500 g: this results in a very compact, but nevertheless functional and long-term usable gas bearing, in which both the Start-up, as well as in the run-out phase, a contact-free storage of the mutually moving bearing parts is avoided and that acts as a hydrodynamic bearing at high operating speed (about 10,000 to 30,000 rpm), whereby only compressed gas of relatively low pressure is required, so that a conventional

Nippon Telegraph & Telephone Public Corp.

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Pat 129 / 3-79M 030029/0892

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Licher rotary compressor can be used for a long time without the need for relubrication.

Fig. 9 shows a bearing structure that differs from the 4 and 5 differs in that a shaft collar 11 'with a plurality of known, herringbone patterns attached grooves 17 is used shallow depth. Compressed air bearings with such inclined grooves are known and are used for the purpose to generate a hydrodynamic pressure for the Storage of the shaft collar to draw outside air into the bearing during rotation. With conventional bearings made this training because of the contact between the shaft collar and bearing shell during the start-up and During the run-out phase of the bearing a hardening of the bearing shell surface is necessary, for which e.g. ceramic materials are used will. However, this not only increases the manufacturing costs for the bearing, but also decreases it also its usability and duration of use. The embodiment of a shown in Fig. 9, however Pressurized gas bearing according to the invention makes it possible to have storage during the start-up and run-down phase of the movement to ensure that there is no contact between the moving parts, which is achieved through the intermittent use of compressed air from such a small and functionally reliable compressed air source as e.g. a turbo compressor is possible.

In Figs. 10a and 10b, a thrust bearing is with a bearing washer 22 is shown, which is used to mount a support part (i.e. a support part to be supported) Element) 21 is provided and adapted accordingly. The bearing disk 22 is designed as a circular disk and provided with a central opening 29 and with two concentrically arranged circular grooves 23 and 24, one of which (23) is attached near the central opening 29, while the other (24) is near the outer one The periphery of the bearing disk runs. Every groove is with

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Pat 129 / 3-79M 030029/0892

BATH ORIGINAL

- si - ο π π 1π

% Za * 5 UUIU

a variety of (in the illustrated embodiment: three) provided in the circumferential direction of the groove offset from each other gas supply channels 25 which are each connected to a common circular gas chamber 26 designed as a gas passage, which is in turn connected to a source of pressurized gas 27. The pressurized gas is from the camp to the outside through the Bearing gap or the bearing play 28 and released again through the central opening 29. The circular grooves 23 and 2 4 can be carried out in the same way as in the bearing examples already described above, with the restriction that the values for the diameters of the inner and outer annular grooves 23 and 24 in the next The above formula must be used instead of the value D.

In the bearing shown in FIGS. 4 and 5, the bearing length L is relatively small and the distance between the annular grooves 13 at the two bearing ends is smaller than the circumferential spacing of the air supply ducts 14 (ie a corresponding circular arc length for a central angle of 120 °). With this arrangement, the variation in the pressure curve over the length of the bearing is small, so that the axial pressure distribution changes with an increase or decrease in the bearing play, as can be seen from the trapezoidal curves A and A 'in FIG. A represents the axial pressure curve in the high pressure area of the bearing, and A ^{1 represents} the pressure curve in the low pressure area of the bearing. The dashed pressure curves B and B ¹ also shown in FIG. 11 result for the case already described in more detail above and in which either the bearing length is greater than the bearing diameter or there is a relatively large number of air supply ducts (lowering of the pressure in the high pressure area of the bearing, increase of the pressure in the low pressure area of the bearing due to increased flow resistance in

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Pat Ϊ29 / 3-79Μ _{D3002 9/089} 2

axial direction and the resulting partial radial deflection of the pressure fluid from the high pressure area in the low pressure range).

In the gas bearing shown in FIG. 12 and designed as an axial and radial bearing, this problem is solved. In the case of the bearing shown, a radial bearing is of a relatively large bearing length with a thrust bearing, as is the case in FIG Principle from FIGS. 10a and 10b can be taken, combined. In the illustrations according to FIGS. 12, 13 and 14, a main bearing body 32 of the bearing is received in an annular groove / that of a narrowed diameter portion 31a of a shaft 31 and its vertical side walls 31b is formed. The joints between the radial bearing surface 32a of the bearing main body 32, which has an extension in the axial direction, and the two axial pressure surfaces 32b, whose each extends in the radial direction, are angled obliquely and delimit the angled sections at this point in a circle circumferential annular channels 34 which through gas outlet channels 33 provided for the rotating shaft 31 with the atmosphere surrounding the bearing are connected. The formation of the two annular channels 34 and the gas outlet channel 33 prevents there is interference between the radial bearing and the thrust bearing.

In the center of the radial bearing surface 32a is an annular gas outlet groove 35 is provided, which divides the radial bearing surface 32a into two individual surfaces. The ring groove 35 is in communication with the outside of the bearing via a radial outlet 36 in the rotatable shaft 31 .. Near the annular channels 34 and the dividing annular groove 35, further annular grooves 37 are provided, each of which is three Has gas supply channels 39 of small diameter, the are arranged uniformly offset from one another in the circumferential direction of the annular groove and have a gas passage 38 Nippon Telegraph & Telephone Public Corp.

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Pat 129 / 3-79M 030029/0892

are in communication in the main bearing body 32. Each axial bearing surface 32b is provided with circular grooves 310 in the Provided near their inner and outer boundary edges and each circular groove 310 is in communication with the gas passage 38 via three gas supply channels 311 which are evenly spaced apart from one another. A Gas passage 312 designed as a nipple is still there intended to connect the gas passage 38 to the compressed air source = for a bearing construction, in which the gas outlet channel 33 is to be closed, an outlet opening 313 can also be provided in the radial direction (as shown in Fig. 14) are provided.

The pressurized gas supplied to the nipple 312 is from there to the gaps between the radial bearing surface 32a and the section which is narrowed in diameter of the shaft 31 and between the axial bearing surfaces 32b and the vertical side walls 31b at the narrowed portion on the rotating shaft 31 via the air passage 38 and the gas supply channels 39 and 311 forwarded to the Build up bearing pressure to support the shaft 31.

In the embodiment shown in FIG. 12, the radial surface 32a is divided into two individual sections by the annular groove 35 connected to the outlet 36, the ratio of the bearing diameter to the bearing length being selected to be essentially less than 1, for example approximately 0.5. According to the design of this embodiment, the effective bearing length is reduced by the central annular groove, whereby a pressure distribution can be achieved, as shown in curves A and A ¹ in FIG. 11, in order to improve the bearing efficiency. In general, it is advantageous to choose the axial distance between the gas supply channels so that it is approximately 2/3 to 1/2 of the bearing length. A distance of less than 1/2 of the storage length cannot impair the storage effectiveness.

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Pat 129 / 3-79M 030029/0892

improve. If one wants to increase the bearing capacity of the warehouse by enlarging it raise the bearing length of the radial bearing, then the radial bearing surface can also be divided into three or four Individual sections by arranging two or three annular grooves each connected to an outlet channel split up. In this case, for example, for each individual section the bearing surface then has two ring grooves with connected air supply channels for the supply of compressed air provide there.

Whereas in the radial bearing shown in FIG. 12, the radial bearing surface is so divided by the annular groove 35 became that over a relatively long range of the bearing length there was an essentially uniform pressure distribution can be achieved, the same purpose is achieved in another embodiment shown in FIG. that the annular grooves 37 are connected to one another via a plurality of axial grooves 314, each of these The axial grooves 314 are designed to be less deep than the annular grooves 37 is. In Fig. 15, 31 'is the rotating Lawelle designated.

Although in the embodiments shown so far, the annular grooves are provided in the bearing shell were, the invention is by no means limited to this arrangement of the annular grooves. Rather, let yourself achieve the advantages of the invention also by arranging the annular grooves in the shaft, like this is shown in Fig. 16: In detail there is a rotatable shaft collar 41 used with rings is provided around its outer circumference extending annular grooves 42a, while the bearing surface of the bearing shell is provided with air supply channels 44a, which the annular grooves 43a are opposite. A thrust bearing pressure plate 48 attached to the shaft (preferably integral with the this is formed), is provided with concentric annular grooves 43b as in the embodiment according to FIG. 10b, and furthermore are air supply channels 44b in the axial bearing surfaces

Nippon Telegraph & Telephone Public Corp.

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BATH ORIGINAL

the bearing shell 42 is provided so that they are opposite to the annular grooves 43b. The air supply channels 44a and 44b are in turn connected to an air chamber 45. There are still annular grooves on the shaft collar 41 46 arranged, which - as described above, in turn as partial grooves for the radial bearing surface to serve. Associated with them, outlet channels 47a are provided in the fixed bearing body, which in the radial Merge into storage area. Furthermore, outlet channels 47b are in the thrust bearing- ^ O pressure plate to prevent undesired Interference is provided between the radial and thrust bearings.

When using such dividing grooves as are provided, for example, in the exemplary embodiment according to FIGS. 12 and 16 are, compressed air is admitted into the bearing gap via the dividing grooves 37 (Fig. 12) or 43a (Fig. 16), the one across the bearing gap with that from the other, at the other end of the same bearing section existing annular groove exiting compressed air the pressure pad within the bearing gap for the relevant Storage area forms. The durch.das bearing play between the dividing grooves 35 and 46 and the air supply ring grooves 37 and 4 3a adjacent to them formed intermediate channel provides a connection for air emerging from the air cushion to the outlets 36 or 47a and thus to the outside of the bearing, so that on this way again air from the bearing can emerge.

Nippon Telegraph & Telephone Public Corp.

Tokyo / Japan

Pat129 / 3-79M _O3 oo29 / O892

BATH ORIGINAL

Claims (15)

GEYER, HAGEMANN & PARTNER Drstouchesstraße 60 · Postfach 400745 · 8000 Munich 40-Telephone 089/3040 7T Telex 5-2161) 6 hagre! Telegram haf-eypalrnt fax machine 089/304071 -S- Nippon Telegraph & Telephone Munich, the Public Corporation Tokyo / Japan January 12, 1980 u.z .: Pat 129 / 3-79M Dr.G / 2 / he PATENT CLAIMS (1 · ι gas bearing, in which, to support a rotating shaft, gas under pressure from a compressed gas source can be fed to a bearing gap between a bearing shell and the shaft, characterized in that the bearing shell (12) has a plurality of annular grooves (13) extending in its circumferential direction, which extend along the entire inner bearing surface, ■ are axially offset from one another and are open to the bearing gap (Cr),
that a plurality of small-diameter gas supply channels (14) arranged offset to one another at an angle are provided, each of which is connected to associated annular grooves (13), and that a gas passage (15) for connecting the gas supply channels (14) is provided with the compressed gas source (16). 2. Gas bearing according to claim 1, characterized in that each annular groove is arranged away from one end of the bearing by a distance (L ₁ ) of about 5 to 15% of the total bearing length (L). 030029/0892 " ² " 3. Gas bearing according to claim 1 or 2, characterized in that the depth (g) of the annular grooves (13) is approximately that 1.5 to 6 times the bearing play (Cr). 4. Gas bearing according to one of claims 1 to 3, characterized in that the gas supply channels (14) in Circumferential direction are attached offset from one another at substantially the same distance. 5. Gas storage according to one of claims 1 to 4, characterized characterized in that a plurality of oblique to the shaft axis extending grooves (17) in herringbone pattern are mounted on the surface of the shaft (11 '). 6. Gas bearing, in which a gas under pressure from a pressurized gas source to support a support part Bearing gap between a bearing disk of a thrust bearing in the form of a circular plate and can be fed to the support part, characterized in that the bearing washer (22) has a central opening (29) and a bearing surface with several concentrically arranged circular grooves (23, 24) is provided, the innermost (23) in the vicinity of the central opening (29) and the outermost (24) in the vicinity of the Outer circumference of the bearing washer (22) is attached, and that a plurality of in the circumferential direction of the circular groove (24) offset from one another arranged gas supply channels (25) of small diameter are provided, which each are in communication with associated circular grooves (24) and with the compressed air source via gas passages (26) (27) are connected. 7. Gas bearing according to claim 6, characterized in that the innermost circular groove (24) from the central opening (29) and the outermost circular groove (24) from the outer circumference of the bearing disk (22) each have a distance of about 5 to 15% of the size of the bearing diameter. Nippon Telegraph & Telephone Public Corp. Tokyo / Japan _ ο _ Pat 129 / 3-79M 030029/0892 8. Gas bearing according to claim 6 or 7, characterized in that the depth of the circular grooves (24) is approximately that 1.5 to 6 times the value of the bearing gap (28). 9. Gas bearing according to one of claims 6 to 8, characterized in that the gas supply channels (25) are attached offset from one another in the circumferential direction of the bearing disc (22) with essentially the same distance.
10 10. Gas storage according to one of claims 1 to 5, characterized characterized in that at least one annular groove (35) is provided for dividing the inner bearing surface (32a) which is in communication with a radial outlet (36), and that near this dividing groove (35) further annular grooves (37) with a plurality of in the respective further annular groove (37) opening gas supply channels (39) are provided. 11. Gas storage according to one of claims 1 to 5 or 10, characterized in that a plurality of axial Grooves (314) are provided which connect the annular grooves (13; 13 '; 37) to one another and their depth is smaller is designed as the depth of the annular grooves (13; 13 '; 37). 12. Gas bearing in which a rotatable shaft for the formation of axial and radial bearing support surfaces with a section narrowed in diameter is provided in which a bearing shell engages, with gas under pressure from a pressurized gas source bearing gaps is supplied, each between the bearing surfaces of the bearing shell and the individual support surfaces of the diameter narrowed shaft collar, characterized in that Nippon Telegraph & Telephone Public Corp. Tokyo / Japan - 4 - Pat 129 / 3-79M Ö30Q23 / 0 & 92 -A- that the radial bearing a radial bearing surface (32a), several annular grooves running in the circumferential direction (37) along the entire inner peripheral surface of the radial bearing surface (32a) near the bearing ends run and axially offset from one another and are open to the radial bearing gap, a plurality of small-diameter gas supply channels (39) which are offset from one another at an angle for each annular groove (37), the gas supply channels (39) each with their associated annular grooves (37) related, and a gas passage (312, 38) for connecting the gas supply channels (39) with the pressurized gas source, that the thrust bearing axial bearing surfaces (32b) each with a plurality of circular grooves open towards the respective axial bearing gap (310), the innermost near the radial bearing surface (32a) and the outermost near the non-narrowed radial outer circumference of the rotatable shaft (31) lies, as well as a plurality of gas supply channels (311) of small diameter for the circular grooves (310), each of which is in communication with the associated circular groove (310) in order to connect it to the gas passage (312, 38),
having, and that connecting lines between the radial bearing surface (32a) and the axial bearing surfaces (326) via outlets (33; 312), which extend through the shaft (31), are in communication with the environment. 13. Gas storage according to claim 12, characterized in that that at least one annular groove (35) is provided which divides the inner bearing surface (32a) of the radial bearing and which is connected to a radial outlet (36), Nippon Telegraph & Telephone Public Corp. _ 5 _ Tokyo / Japan * ^ _{ΛΛΑΛίΛΛΛ} «
Pat 129 / 3-79M 030029/0892 D - that even further circumferential annular grooves (37) are arranged near the dividing annular groove (35), and that a plurality of these further circumferential annular grooves (37) assigned, each in the assigned Annular groove (37) opening gas supply channels (39) are provided. 14. Gas bearing, which is designed as a radial bearing and with the gas under pressure from a pressurized gas source in a radial bearing gap between a bearing shell and a rotatable shaft to support it Rotation can be initiated, characterized in that the bearing shell with a plurality of at an angle to one another staggered arranged gas supply channels (44a) is provided of small diameter, which open to the bearing gap and are attached near both ends of the bearing (42), that a gas passage (45) for connecting the gas supply channels (44a) is provided on the compressed air source, and that on the rotatable shaft (41) several circumferential Annular grooves (43a) are attached, which are opposite at the mouths of the gas supply channels (44a) Places on the shaft (41) are provided and are open to the bearing gap. 15. Gas bearing, which is designed as a thrust bearing and in which gas under pressure from a pressurized gas source in the bearing gap between a bearing surface and a rotatable shaft collar for rotational support can be introduced is, characterized in that the rotatable shaft collar (41) is integrally formed with it axial bearing plates (48) which oppose the two axial end surfaces of the bearing shell (42), each of the bearing plates (48) with several concentrically arranged circular grooves (43b) open towards the bearing gap is provided, the innermost close to the inner peripheral surface of the bearing (42) and its outer close to the outer Nippon Telegraph & Telephone Public Corp. Ä 030029/0892 circumference of the axial bearing plate (48) is attached, and that the bearing shell (42) with several concentric arranged, axially only short gas supply channels (44b), which are open to the respective bearing gap are opposite to the concentric circular grooves (43b) of the shaft collar (41), offset from one another at an angle and are connected to the source of pressurized gas via a gas passage (45). Nippon Telegraph & Telephone Public Corp. Tokyo / Japan - 7 - Pat 129 / 3-79M 030029/0892