Gas bearing

Abstract

The invention provides a gas bearing which is easy to design and does not require a special structure for adjusting the shape or size of a bearing surface. A gas bearing is provided with: a sleeve having a rigid bearing surface; and a support structure that elastically supports the sleeve from the outside in the radial direction thereof, and that is provided over the entire region of the sleeve in the circumferential direction. A preferred support structure is configured from an aggregate of a plurality of beams. Preferably, the beam is composed of a cantilever beam or a two-end supporting beam. A preferred support structure is configured from an aggregate of a plurality of beams. Preferably, the beam is composed of a cantilever beam or a two-end supporting beam.

Description

Technical Field

[0001] This invention relates to a gas bearing that uses air or other gases as a lubricating medium. Background Technology

[0002] As an example of a gas bearing, a foil bearing is known. A foil bearing is a bearing whose bearing surface is composed of a flexible film with low rigidity to bending, such as a metal foil, tape, or film. Because the load on the supported shaft is borne by the deflection of the film, the accuracy of the shaft's center position is relatively poor, but it possesses high-speed stability.

[0003] Patent Document 1 discloses a gas bearing that allows adjustment of the shape or size of the bearing surface even after assembly. The gas bearing of Patent Document 1 comprises: a housing having a tapered inner surface; a sleeve having a tapered outer surface that engages with the tapered inner surface; and an axial position adjustment mechanism for adjusting the relative axial position of the housing and the sleeve.

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 7-119746 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] The design of foil bearings requires combining fluid lubrication analysis focusing on the gas film with structural analysis focusing on the deformation of the film, making the design process complex.

[0009] In addition to the bearing elements, the structure of the bearing surface also needs to be adjusted for the gas bearing in Patent Document 1.

[0010] The purpose of this invention is to provide a gas bearing that is easy to design and does not require special adjustment of the shape or size of the bearing surface.

[0011] means for solving technical problems

[0012] The gas bearing of the present invention comprises: a sleeve 11 having a rigid bearing surface 12; and a support structure 15 that elastically supports the sleeve 11 from its radially outer side and is disposed over the entire circumferential region of the sleeve 11.

[0013] Invention Effects

[0014] According to the present invention, a gas bearing with a structure that is easy to design and does not require special adjustment of the shape or size of the bearing surface is provided. Attached Figure Description

[0015] Figure 1This is a diagram illustrating the basic structure involved in an embodiment of the gas bearing of the present invention.

[0016] Figure 2 This diagram illustrates the gas bearings involved in the basic structure.

[0017] Figure 3 This is a diagram showing the gas bearing according to the first embodiment.

[0018] Figure 4 This is a diagram illustrating the rigidity of the gas bearing according to the first embodiment.

[0019] Figure 5 This is a diagram showing the gas bearing according to the second embodiment.

[0020] Figure 6 This is a diagram showing another gas bearing involved in the second embodiment.

[0021] Figure 7 This is a diagram showing the gas bearing according to the third embodiment.

[0022] Figure 8 This is a diagram showing the gas bearing according to the fourth embodiment.

[0023] Figure 9 This is a diagram showing a gas bearing that supports a rotating shaft.

[0024] Figure 10 This is a diagram illustrating an example of the shape of the bearing surface that can be used in the air bearing of the present invention. Detailed Implementation

[0025] Hereinafter, embodiments will be described with reference to the accompanying drawings. This invention includes multiple embodiments; however, the basic structure common to these embodiments will be described first, followed by descriptions of more specific embodiments in turn.

[0026] [Basic structure of the implementation method: Reference] Figure 1 , Figure 9 , Figure 10 ]

[0027] Figure 1 The gas bearing 1 shown includes: a sleeve 11 that houses a rotating shaft 100 on its inner side; and a support structure 15 that elastically supports the sleeve 11 from its radially outer side. In the gas bearing 1, the support structure 15 is elastically deformable, while the sleeve 11 has a rigid bearing surface 12. The support structure 15 is disposed over the entire circumferential region of the sleeve 11.

[0028] [Function of rigid bearing surface 12]

[0029] In a gas bearing, a thin film of gas (hereinafter referred to as a gas film) is generated between the bearing surface and the shaft, which is drawn in by the rotation of the shaft.

[0030] In the case of foil bearings, the top foil, which forms the bearing surface, is very thin and therefore deforms under the pressure of the gas film. If the top foil deforms, the circumferential distribution (shape) of the gas film changes, and consequently, the pressure distribution of the gas film also changes. Thus, the pressure distribution of the gas film and the deformation of the top foil are mutually influential. Therefore, when designing foil bearings, it is necessary to combine fluid lubrication analysis focusing on the gas film with structural analysis focusing on the deformation of the foil.

[0031] As with the gas bearing 1 of the present invention, if the bearing surface 12 is rigid, the bearing surface 12 will not deform due to the presence or shape of the gas film, thus maintaining the shape of the bearing surface 12. Therefore, the bearing surface 12 and the gas film do not affect each other and can be considered independent.

[0032] Here, it is explained that the bearing surface 12 is rigid, but hereinafter, it is assumed that the sleeve 11 including the bearing surface 12 is rigid as a whole.

[0033] [Function of flexible support structure 15]

[0034] The sleeve 11 is rigid, while the support structure 15 is configured to be elastically deformable and elastically support the sleeve 11. The sleeve 11 is rigid and does not undergo elastic deformation, but during the process of supporting the rotating shaft 100, it may sometimes displace radially RD. The support structure 15 withstands the displacement of the sleeve 11 through elastic deformation.

[0035] Here, the rigidity of sleeve 11 does not mean that sleeve 11 is made of a completely rigid body, but rather that it possesses a degree of rigidity that prevents elastic deformation due to the supporting rotating shaft 100. Even if sleeve 11 is made of the same material, it can sometimes be described as rigid and sometimes as not rigid, depending on the supporting rotating shaft 100. The elastic deformation of the support structure 15 is also subject to the same conditions as the rigidity of sleeve 11, which is determined not only by the material but also by the fact that it is used as a gas bearing 1.

[0036] [Manufacturing process used]

[0037] Considering that the mechanical precision of the constituent components affects the performance of foil bearings, it is desirable to employ a manufacturing process similar to that used for gas bearing 1. For example, to meet dimensional accuracy requirements, the sleeve 11 and support structure 15 of the gas bearing 1 can be manufactured using methods such as machining, electrical discharge machining, AM (Additive Manufacturing), or injection molding. Therefore, based on the gas bearing 1, it is possible to manufacture gas bearings with high mechanical precision in dimensions and shape, and to suppress deviations in bearing characteristics.

[0038] The material used to construct the gas bearing 1 is arbitrary; metallic materials are particularly suitable, but resin materials can also be used. In cases like rolling bearings where the inner ring, outer ring, and rolling elements are constantly sliding, bearing steel (JIS SUJ) is used to account for sliding wear. However, in the case of the gas bearing 1, even if sliding occurs between the components, it is less than in rolling bearings. Therefore, there are many options for the material of the gas bearing 1.

[0039] [Example of support structure 15: See reference] Figure 2 ]

[0040] Some structural details of the support structure 15 are described below. Additionally, Figure 2 In the example shown, a housing 17 is provided around the support structure 15. In this example, the support structure 15 is provided between the housing 17 and the sleeve 11. However, sometimes in mechanical devices that use gas bearings, a component corresponding to the housing 17 is also provided. Therefore, the housing 17 is an option in this invention.

[0041] Furthermore, Cmp.1, Emb.1, and Emb.2 are exemplified here. Cmp.1, Emb.1, and Emb.2 differ in the structure of the support structure 15 on the circumferential CD.

[0042] In addition, such as Figure 2 As shown, the horizontal direction H and the vertical direction V are defined when using a gas bearing.

[0043] Cmp.1 is part of the circumferential CD and has support structures 15 provided only in the direction of the rotational shaft's own weight. These support structures 15 are provided only with the consideration of supporting loads on the shaft (not shown). However, in reality, due to shaft oscillation or external vibrations, loads are also applied to the gas bearing 1 in directions other than the direction of its own weight. Therefore, as shown in Emb.1 and Emb.2, if arranged over the entire area of ​​the circumferential CD, the shaft can be supported for loads in directions other than its own weight. Moreover, the support structure 15 of Emb.1 has a periodic structure in addition to spanning the entire area of ​​the circumferential CD. Although the support structure 15 of Emb.2 also spans the entire area of ​​the circumferential CD, it does not have a periodic structure but a non-periodic structure.

[0044] Since the bearing surface 12 of the gas bearing with the above basic structure is rigid, the deformation of the bearing surface 12 and the pressure distribution of the gas film are independent, thus making the design easy.

[0045] Furthermore, gas bearings with a basic structure have a support structure in addition to the direction of the rotation shaft's own weight, so they can respond to loads other than their own weight, such as vibrations of the rotation shaft, and thus achieve stable high-speed rotation.

[0046] Gas bearings with a basic structure can be manufactured through machining, AM (engineering), and injection molding, thus enabling high-precision bearing manufacturing and suppressing deviations in bearing characteristics.

[0047] The basic structure and effects of the gas bearing 1 involved in this invention are as described above. However, more specific examples of the gas bearing 1 will be described in turn.

[0048] [First Implementation Method: Reference] Figure 3 ]

[0049] refer to Figure 3 The gas bearings 1A to 1F according to the first embodiment will be described. Gas bearings 1A to 1F share a common structure in that they include a sleeve 11, a support structure 15, and a housing 17, but the specific structure of the support structure 15 differs. The support structure 15 is composed of multiple beams 16 that generate bending stress between the sleeve 11 and the housing 17 primarily through the load on the bearing from the rotation of the sleeve 11, and transmit this stress to the housing 17. That is, the support structure 15 is an assembly of multiple beams 16 disposed between the sleeve 11 and the housing 17. The shape and arrangement of the beams in gas bearings 1A to 1F differ.

[0050] [Gas Bearing 1A]

[0051] Gas bearing 1A comprises a support structure 15 consisting of multiple cantilever beams 16A bent into an arc shape. Each cantilever beam 16A is connected to a housing 17 via a fixed end 16A1, and a free end 16A2 is located between a sleeve 11 and the housing 17. Specifically, the cantilever beams 16A of gas bearing 1A are bent radially RD. Between the fixed end 16A1 and the free end 16A2, at the apex of the arc when viewed from one side of the housing 17 (i.e., the contact point 16A3), the cantilever beam 16A connects to the sleeve 11. In gas bearing 1A, eight cantilever beams 16A are arranged at equal intervals along the circumferential direction CD. The multiple contact points 16A3 engage with the sleeve 11, thus forming a single unit for gas bearing 1A. Gas bearings 1B to 1F are similarly integrated.

[0052] The shape of the cantilever beam 16A is the shape seen when the gas bearing 1A is viewed from the front. Furthermore, the cantilever beam 16A is continuous in the direction of the axis C of the gas bearing 1A. The same applies to other gas bearings.

[0053] [Gas Bearing 1B]

[0054] The gas bearing 1B comprises a support structure 15 consisting of multiple inclined beams 16B1 and 16B2 tilted relative to the radial direction RD. Inclined beams 16B1 are connected to both the sleeve 11 and the housing 17, and are inclined clockwise as shown in the figure. Inclined beams 16B2 are connected to both the sleeve 11 and the housing 17, and are inclined counterclockwise as shown in the figure. A pair of inclined beams 16B1 and 16B2 are rigidly connected to the sleeve 11 at one end and to the housing 17 at the other end. In other words, the support structure 15 in the gas bearing 1B constitutes a frame structure consisting of a combination of triangular inclined beams 16B1 and 16B2, the sleeve 11, and the housing 17.

[0055] [Gas Bearing 1C]

[0056] Like gas bearing 1B, gas bearing 1C also features a frame structure for its support structure 15. In the frame structure of gas bearing 1B, one end (on one side of sleeve 11) and the other end (on one side of housing 17) of a pair of diagonal beams 16B1 and 16B2 are rigidly connected together. In contrast, in gas bearing 1C, while one end (on one side of sleeve 11) of a pair of diagonal beams 16B1 and 16B2 are rigidly connected together, the other ends (on one side of housing 17) are each independently rigidly connected to housing 17. That is, compared to gas bearing 1B, gas bearing 1C increases the number of points supporting housing 17.

[0057] In gas bearings 1B and 1C, the diagonal beam units, consisting of a pair of diagonal beams 16B1 and 16B2, are continuously arranged in the circumferential direction CD. However, for example, the diagonal beam units can also be arranged intermittently in the circumferential direction CD. More specifically, in gas bearing 1B, eight diagonal beam units can be seamlessly arranged at 45° intervals, or four diagonal beam units can be arranged at 90° intervals. In this case, the support structure 15 is provided throughout the entire circumferential region.

[0058] [Gas Bearing 1D]

[0059] The gas bearing 1D is supported by multiple end-bearing beams 16D bent into an arc shape, forming a support structure 15.

[0060] One end of the two-end support beam 16D is fixed to the sleeve 11, and the other end is fixed to the housing 17. Multiple two-end support beams 16D are arranged at equal intervals or periodically in the circumferential direction CD. The two-end support beams 16D are bent in the same direction in the circumferential direction CD.

[0061] [Gas Bearing 1E]

[0062] The gas bearing 1E has a support structure 15 consisting of multiple thin plates forming a curve resembling an involute. One end of each end support beam 16E is fixed to a sleeve 11, and the other end is fixed to a housing 17. Multiple, specifically three end support beams 16E, are arranged at equal intervals or periodically throughout the circumferential region CD.

[0063] [Gas Bearing 1F]

[0064] The gas bearing 1F is supported by a support structure 15 consisting of multiple straight cantilever beams 16F. One end 16F1 of each cantilever beam 16F is fixed to the housing 17, while the other end 16F2 forms a free end. The contact point 16F3 between one and the other ends of the cantilever beam 16F connects to the sleeve 11. Multiple, specifically three end-support beams 16E, are arranged at equal intervals or periods in the circumferential direction CD.

[0065] Adjustment of stiffness in gas bearing 1A: Reference Figure 4 ]

[0066] In the gas bearing 1A, when the sleeve 11 is engaged with the support structure 15, the sleeve 11 is supported by all the cantilever beams 16A, including (1) and (3) and (2) and (4) arranged above and below the load L, when a load L is applied. Therefore, similar to the design of foil bearings, if the cantilever beams 16A are designed with only the rigidity RV in the load direction (vertical direction V) in mind, the rigidity becomes greater than required. Therefore, it is necessary to design the cantilever beams 16A considering both the rigidity RV and the rigidity RH orthogonal to the rigidity RV. At this time, if the rigidity RV can be made greater than the rigidity RH, the increase in bearing rigidity caused by the rigidity RH can be relatively ignored, thus making the design of the cantilever beams 16A easier.

[0067] Even for gas bearings 1B to 1F, the load direction and rigidity in the direction orthogonal to it can be adjusted by designing the shape and size of the beams constituting the support structure 15. For example, the end support beams 16E of gas bearing 1E and the cantilever beam 16F of gas bearing 1F have a vertical rigidity RV < horizontal rigidity RH. Furthermore, the end support beams 16D of gas bearing 1D have a vertical rigidity RV > horizontal rigidity RH.

[0068] [Effects of the first embodiment]

[0069] Gas bearings 1A to 1F are integrally structured and do not consist of multiple components, thus eliminating assembly errors. Therefore, gas bearings 1A to 1F can reduce manufacturing errors.

[0070] Next, based on gas bearings 1A to 1F, by adjusting the rigidity of the support structure 15, it is possible to make it have arbitrary rigidity in any direction, thus obtaining the desired bearing performance.

[0071] Furthermore, if the radial stiffness is greater than the circumferential stiffness, then we only need to focus on the radial stiffness, which makes it easy to conduct research on the support structure 15 based on the theoretical formula.

[0072] [Second Implementation Method:] Figure 5 , Figure 6 ]

[0073] Next, refer to Figure 5 and Figure 6 The gas bearings 2A to 2D according to the second embodiment will be described.

[0074] The second embodiment discloses gas bearings 2A to 2D that possess frictional damping elements. In addition to possessing the elements of the first embodiment, the gas bearings 2A to 2D also possess frictional damping elements within the space of the support structure 15. The content of the frictional damping elements included in the support structure 15 of the gas bearings 2A to 2D differs.

[0075] [Gas bearing 2A: Reference] Figure 5 ]

[0076] Gas bearing 2A uses the same cantilever beam 16G made of thin plate as gas bearing 1E in the first embodiment. Gas bearing 2A divides multiple cantilever beams 16G into three groups G1, G2, and G3, in which cantilever beams 16G overlap with adjacent cantilever beams 16G. A particular cantilever beam 16G has a fixed end on the housing 17 side and also a fixed end on the sleeve 11 side. In each group G1, G2, and G3, the other end of the particular cantilever beam 16GI located on the innermost radial side RD is integrated with the sleeve 11. Thus, the sleeve 11 is elastically supported by the support structure 15. In each group G1, G2, and G3, adjacent cantilever beams 16G are slidably in contact with each other.

[0077] When the gas bearing 2A supports the rotating shaft and a load W is applied in the vertical direction V, the sleeve 11 supported by the cantilever beam 16G displaces in the vertical direction V. If the displaced sleeve 11 pushes down on the other cantilever beams 16G, the other cantilever beams 16G are supported in a cantilever shape, and therefore the overlapping surfaces slide against each other, generating friction. Vibration damping is achieved due to this friction, especially enabling stable high-speed rotation. In addition, the gas bearing 2A possesses the first friction damping element of this invention.

[0078] [Gas bearing 2B: Reference] Figure 5 ]

[0079] The gas bearing 2B has a support structure 15 consisting of multiple cantilever beams 16H bent into arc shapes. The cantilever beams 16H are similar to the cantilever beam 16A in the first embodiment, but their free ends extend further towards the housing 17 than those of the cantilever beam 16A. Furthermore, the portion in contact with the housing 17 folds back towards the sleeve 11. This folded-back curved surface 16H1 slidably contacts the inner circumferential surface 17I of the housing 17. Additionally, portions identical to those of the cantilever beam 16A are labeled with the same symbols as those of the cantilever beam 16A, and further explanation is omitted.

[0080] In the gas bearing 2B, when the supporting rotating shaft is supported and a load L is applied in the vertical direction V, friction is generated between the multiple curved surfaces 16H1 and the inner peripheral surface 17I of the housing 17. Therefore, the vibration damping caused by this friction enables particularly stable high-speed rotation. In addition, the gas bearing 2B has the third friction damping element of the present invention.

[0081] [Gas Bearing 2C: Reference] Figure 6 ]

[0082] The gas bearing 2C has a support structure 15 consisting of multiple cantilever beams 16I bent into arc shapes. A sliding plate 16I1 is provided on one side of the free end of the cantilever beam 16I, and the sliding surface 16I2 is slidably in contact with the inner circumferential surface 17I of the housing 17 on the outer side of the radial RD facing the sliding plate 16I1.

[0083] In the gas bearing 2C, when the supporting rotating shaft is supported and a load W is applied in the vertical direction V, friction is generated between the multiple sliding surfaces 16I2 and the inner peripheral surface 17I of the housing 17, thus achieving a vibration damping effect. Furthermore, the gas bearing 2C incorporates the third friction damping element of this invention.

[0084] Gas Bearing 2D: Reference Figure 6 ]

[0085] The support structure 15 in the gas bearing 2D includes inclined beams 16J1, 16J2 and 16J3, 16J4 inclined relative to the radial direction RD. Of the inclined beams 16J1 and 16J2, inclined beam 16J1 is positioned closer to the paper plane than inclined beam 16J2. Figure 6 The two oblique beams 16J3 and 16J4 are located on the deeper side of the paper and intersect each other. Of the two oblique beams 16J3 and 16J4, oblique beam 16J3 is positioned closer to the paper surface than oblique beam 16J4. Figure 6 ( ) on the deep side, and intersecting with each other.

[0086] The diagonal beams 16J1 and 16J2 form a cantilever beam with the sleeve 11 side being the fixed end and the shell 17 side being the free end 16J5. The free end 16J5 is, in an example, only a small distance away from the inner circumferential surface 17I of the shell 17, but it can also be in contact with the inner circumferential surface 17I.

[0087] One side of the sleeve 11 of the diagonal beams 16J3 and 16J4 is a fixed end, and one side of the shell 17 is also a fixed end, forming a beam supporting both ends.

[0088] In the gas bearing 2D, when the supporting rotating shaft is supported and the load W is applied in the vertical direction V, friction is generated between the multiple free ends 16J5 and the inner circumferential surface 17I of the housing 17. Therefore, the vibration damping caused by this friction results in particularly stable high-speed rotation. The gas bearing 2D also possesses the third friction damping element of the present invention.

[0089] [Effects of the second implementation method]

[0090] Gas bearings 2A to 2D, by incorporating friction damping elements, achieve a damping effect relative to vibration. Therefore, by suppressing the runout of the rotating shaft during rotation and improving the stability of the shaft diameter, exceptionally stable high-speed rotation can be achieved.

[0091] [Third Implementation Method: Reference] Figure 7 ]

[0092] Next, refer to Figure 7 The gas bearings 3A and 3B involved in the third embodiment will be described.

[0093] The third embodiment generates friction through a portion or all of the sliding between the sleeve 11 and the support structure 15, thereby achieving a damping effect. Gas bearings 3A and 3B incorporate the second friction damping element of this invention.

[0094] The basic structure of gas bearings 3A and 3B is the same as that of gas bearing 1A.

[0095] However, in the gas bearing 3A, among a plurality of cantilever beams 16K1 and K2 bent into an arc shape, cantilever beam 16K1 slidably contacts the outer peripheral surface 11O of the sleeve 11 on the contact surface 16K3, while cantilever beam 16K2 engages with the outer peripheral surface 11O of the sleeve 11. Thus, in the gas bearing 3A, the sleeve 11 is supported by cantilever beams 16K1 and K2.

[0096] Furthermore, in the gas bearing 3B, all parts of the multiple cantilever beams 16K1 bent into arc shapes are slidably in contact with the outer peripheral surface 11O of the sleeve 11 through the contact surface 16K3, thereby the sleeve 11 is supported by the support structure 15. The gas bearing 3B is assembled from two components: the sleeve 11 and the housing 17 on which the cantilever beams 16K1 are integrally formed.

[0097] Furthermore, although an example of partial or complete sliding between the sleeve 11 and the support structure 15 is shown here, it is possible to provide a portion that can be partially or completely slidable between the housing 17 and the support structure 15, as another form. Moreover, in the case where the gas bearings 3A and 3B do not have a housing 17, it is possible to provide a portion or completely slidably separable between the housing (which replaces the housing 17) and the support structure 15.

[0098] [Effects of the third embodiment]

[0099] In the third embodiment, similarly to the second embodiment, a damping effect relative to vibration can be obtained by incorporating a friction damping element. Therefore, it is possible to suppress the yaw of the rotating shaft during rotation and improve the stability of the shaft diameter during rotation.

[0100] As with the gas bearing 3B, if all the cantilever beams 16K1 are in contact with the sleeve 11 only through the contact surface 16K3 and the support structure 15 is separated from the sleeve 11, then only the radial RD rigidity is effective, and therefore it is easy to conduct research on the support structure 15 based on the theoretical formula.

[0101] [Fourth implementation method:] Figure 8 refer to〕

[0102] Next, refer to Figure 8 The gas bearings 4A, 4B, and 4C involved in the fourth embodiment will be described.

[0103] The fourth embodiment obtains vibration damping caused by the material damping of the viscoelastic body by sandwiching a viscoelastic body in the sliding part.

[0104] Gas bearing 4A has the same basic structure as gas bearing 3B, but a damping sleeve 18 made of viscoelastic material is provided between sleeve 11 and cantilever beam 16K1, and a damping plate 19 made of viscoelastic material is provided between the inner circumferential surface 17I of housing 17 and the front end of cantilever beam 16K1. Gas bearing 4A can be said to replace the friction-based damping in gas bearing 3B with material damping caused by viscoelastic material.

[0105] Gas bearing 4B has the same basic structure as gas bearing 4A, but a damping body 21 made of rod-shaped viscoelastic body is provided between housing 17 and the free end 16A2 of cantilever beam 16A.

[0106] Gas bearing 4C has the same basic structure as gas bearing 1C, but a damping body 23 made of rod-shaped viscoelastic body is provided between sleeve 11 and housing 17.

[0107] [Effects of the fourth implementation method]

[0108] According to the gas bearings 4A, 4B, and 4C of the fourth embodiment, since a viscoelastic body is sandwiched between the sleeve 11 and the beam 16 and between the housing 17 and the beam 16, or between the two, a higher damping effect is obtained relative to vibration.

[0109] [Postscript]

[0110] The gas bearing based on the present invention is as follows.

[0111] [Postscript 1]

[0112] A gas bearing comprising: Sleeve 11, having a rigid bearing surface 12; and The support structure 15 elastically supports the sleeve 11 from its radial RD outer side and is provided over the entire circumferential area of ​​the sleeve 11.

[0113] [Postscript 2]

[0114] In Appendix 1, the preferred support structure 15 is composed of an assembly of multiple beams 16.

[0115] [Postscript 3]

[0116] In Appendix 2, the preferred beam 16 is composed of a cantilever beam 16A or a beam 16D supported at both ends.

[0117] [Postscript 4]

[0118] In Appendix 1, the preferred support structure 15 is composed of a frame structure.

[0119] [Postscript 5]

[0120] In Appendix 3, it is preferable to have a housing 17 surrounding the support structure 15. Support structure 15 has any one of the following: The first friction damping element consists of multiple cantilever beams 16G that can slide against each other; The second friction damping element is formed by the sliding between multiple cantilever beams 16G and sleeve 11; and The third friction damping element is formed by the sliding between multiple cantilever beams 16G and the housing 17.

[0121] [Postscript 6]

[0122] In Appendix 5, a housing 17 surrounds the supporting structure. A viscoelastic material is sandwiched between the sleeve 11 and the beam 16, or between the shell 17 and the beam 16, or in either of these two locations.

[0123] [Postscript 7]

[0124] In Appendix 1, preferably, a housing 17 surrounds the support structure. The sleeve 11, the support structure 15, and the housing 17 are integrally formed.

[0125] [Postscript 8]

[0126] In any of the appendices 1 to 7, preferably, the bearing surface is either a true circle or formed by offsetting multiple circular arcs.

[0127] In addition to the above, the structures described in the above embodiments can be selected or replaced, or other structures can be appropriately modified.

[0128] For example, the support structure 15 is not limited to an assembly of beams. For example, instead of beam 16, a component that is easily deformed by elasticity, such as rubber, can be arranged between sleeve 11 and housing 17.

[0129] And, as Figure 10As shown, the bearing surface 12 in this invention is not limited to the perfect circular shape shown in (a). As illustrated in (b), (c), and (d) respectively, it can also be shaped with two, three, or four circular arcs (AR), or other shapes that offset multiple arcs. If a bearing surface with multiple arcs is used, the instability force is relatively smaller compared to a perfect circular bearing surface, thus improving vibration stability. For example, if a bearing surface with two arcs offset is used, vibration analysis shows an approximately 25% improvement in vibration stability compared to a perfect circular shape. Furthermore, Figure 10 (b), (c), and (d) exaggerate the amount of offset to make it clear that an offset has been made.

[0130] Symbol Explanation

[0131] 1, 1A, 1B, 1C, 1D, 1E, 1F - Gas bearings; 2A, 2B, 2C, 2D - Gas bearings; 3A, 3B - Gas bearings; 4A, 4B, 4C - Gas bearings; 11 - Sleeve; 11O - Outer circumferential surface; 12 - Bearing surface; 15 - Support structure; 16 - Beam; 16A - Cantilever beam; 16A1 - Fixed end; 16A2 - Free end; 16A3 - Contact point; 16B1, 16B2 - Inclined beams; 16D, 16E - Beams with supports at both ends; 16F 16G, 16GI, 16H, 16I - cantilever beam, 16F1 - one end, 16F2 - the other end, 16F3 - contact point, 16H1 - bending surface, 16I1 - sliding plate, 16I2 - sliding surface, 16J1, 16J2, 16J3, 16J4 - inclined beam, 16K1, 16K2 - cantilever beam, 16K3 - contact surface, 16K5 - front end, 17 - shell, 17I - inner circumferential surface, 18 - damping cylinder, 19 - damping plate, 21, 23 - damping body.

Claims

1. A gas bearing comprising: Sleeve, having a rigid bearing surface; and A support structure that elastically supports the sleeve from its radially outer side and is disposed over the entire circumferential region of the sleeve.

2. The gas bearing according to claim 1, wherein, The supporting structure is composed of an assembly of multiple beams.

3. The gas bearing according to claim 2, wherein, The beam is composed of a cantilever beam or a beam supported at both ends.

4. The gas bearing according to claim 1, wherein, The supporting structure is composed of a frame structure.

5. The gas bearing according to claim 3, comprising a housing surrounding the support structure. The support structure has any one of the following: The first friction damping element is composed of multiple cantilever beams that can slide against each other; The second frictional damping element is constituted by the sliding between the multiple cantilever beams and the sleeve; and The third friction damping element is formed by the sliding between the multiple cantilever beams and the housing.

6. The gas bearing according to claim 5, comprising a housing surrounding the support structure. A viscoelastic body is sandwiched between the sleeve and the beam, and between the housing and the beam, or in both cases.

7. The gas bearing according to claim 1, comprising a housing surrounding the support structure. The sleeve, the support structure, and the housing are integrally formed.

8. The gas bearing according to claim 1, wherein, The bearing surface can be either a true circle or formed by offsetting multiple circular arcs.

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