JP6257965B2 - Foil bearing unit - Google Patents

Description

  The present invention relates to a foil bearing unit.

  A bearing that supports a main shaft of a turbo machine such as a gas turbine or a turbocharger is required to withstand a severe environment such as high temperature and high speed rotation. As a bearing suitable for use under such conditions, a foil bearing has attracted attention. In the foil bearing, a bearing surface is constituted by a thin film (foil) having low rigidity with respect to bending, and the load is supported by allowing the bearing surface to bend. When the shaft rotates, a fluid film (for example, an air film) is formed between the outer peripheral surface of the shaft and the bearing surface of the foil, and the shaft is supported in a non-contact manner.

  For example, Patent Document 1 and Patent Document 2 below show a turbo machine to which a foil bearing is applied.

JP 9-510522 A Japanese National Patent Publication No. 10-511446

  In the turbo machine as described above, it is difficult to fix the foil directly on the inner peripheral surface of the housing provided in the turbo machine. For this reason, normally, as in Patent Documents 1 and 2, a foil bearing cartridge in which a foil is fixed to the inner periphery of a cylindrical case is formed in advance, and the foil bearing cartridge is fixed to the inner peripheral surface of the housing. The assembly work is facilitated. On the other hand, since the operation of fixing the foil to the end surface of the housing is relatively easy, in Patent Documents 1 and 2, the thrust foil is directly fixed to the end surface of the housing.

  By the way, in the foil bearing that supports the shaft in the radial direction and the thrust direction as described above, in order to support the rotating shaft with high accuracy, a foil (radial bearing foil) that supports the radial direction and a support in the thrust direction are provided. The relative positional relationship with the foil to be performed (thrust bearing foil) is important. For this reason, it is necessary to set the relative positional accuracy (for example, perpendicularity) of the attachment surface to which the radial bearing foil is attached and the attachment surface to which the thrust bearing foil is attached with high accuracy. However, in the configuration as described above, the mounting surface of the radial bearing foil is provided on the inner peripheral surface of the case of the bearing cartridge, while the mounting surface of the thrust bearing foil is provided on the end surface of the housing. In order to increase the relative positional accuracy, it is necessary to process and assemble each member with high accuracy, resulting in an increase in manufacturing cost.

  An object of this invention is to provide the foil bearing unit which can support a rotating shaft with high precision, without causing the manufacturing cost to rise.

  In order to achieve the above object, the present invention is attached to a first case member integrally having a cylindrical portion and a flat plate portion extending from the cylindrical portion to an outer diameter, and an inner peripheral surface of the cylindrical portion of the first case member. A radial bearing foil, a thrust bearing foil attached to an end surface of the flat plate portion of the first case member, a shaft portion inserted into the inner periphery of the cylindrical portion of the first case member, and an outer diameter from the shaft portion And an inner member having a flange portion projecting to the inner surface, and the inner member is supported in the radial direction by fluid pressure generated in a radial bearing gap between a bearing surface of the radial bearing foil and an outer peripheral surface of the shaft portion. At the same time, the inner member is supported in the thrust direction by the fluid pressure generated in the thrust bearing gap between the bearing surface of the thrust bearing foil and one end surface of the flange portion.

  In this way, by attaching the radial bearing foil and the thrust bearing foil to the first case member integrally having the cylindrical portion and the flat plate portion, the relative positional accuracy of the mounting surfaces of the two bearing foils, and consequently the radial bearing foil, The relative positional accuracy of the bearing surface (radial bearing surface) and the bearing surface (thrust bearing surface) of the thrust bearing foil can be set with high accuracy regardless of the processing accuracy and assembly accuracy of each member. In this way, a foil bearing unit in which the relative positional accuracy of the radial bearing surface and the thrust bearing surface is set to a high accuracy is created, and this unit is incorporated into a turbo machine or the like, so that the inner member, and eventually the turbo machine or the like can be rotated. The shaft can be supported with high accuracy.

  In the foil bearing unit described above, for example, the shaft portion of the inner member can be constituted by a hollow sleeve portion, and the sleeve portion and the flange portion can be integrally formed. In this way, by forming the sleeve portion and the flange portion of the inner member integrally, the relative positional accuracy between the outer peripheral surface of the sleeve portion facing each bearing surface and the end surface of the flange portion is set with high accuracy. Is done. Further, the inner peripheral surface of the sleeve portion is fitted and fixed to the outer peripheral surface of the rotary shaft of a turbo machine or the like, for example, compared to the case where the flange portion alone is fitted and fixed to the outer peripheral surface of the rotary shaft. Axial dimension increases. Therefore, the relative positional accuracy of the inner member with respect to the rotating shaft (such as the coaxiality of the sleeve portion with respect to the rotating shaft and the perpendicularity of the flange portion) can be set with high accuracy.

  The foil bearing unit further includes, for example, a second case member having a flat plate portion attached to the first case member, and another thrust bearing foil attached to an end surface of the flat plate portion of the second case member. And the inner member is supported in the thrust direction by a fluid pressure generated in a thrust bearing gap between the other end surface of the flange portion of the inner member and the bearing surface of the other thrust bearing foil. . Thereby, with the rotation of the inward member, the flange portion is attached to one end surface of the flange portion and the bearing surface of the thrust bearing foil attached to the first case member, and the other end surface of the flange portion is attached to the second case member. Thrust bearing gaps are formed between the bearing surfaces of the thrust bearing foils, and the inner member can be supported in both thrust directions by the fluid pressure generated in these thrust bearing gaps. Further, in this case, since the first and second case members are engaged with the flange portion from both sides in the axial direction, it is possible to regulate the slipping of the inner member from the first and second case members (bearing cases). The case and the inward member can be handled integrally, and the ease of assembling the foil bearing unit to a turbomachine or the like is improved.

  If a spacer is provided between the first case member and the second case member in the axial direction, the axial distance between the two case members can be set with high accuracy by the spacer. Thereby, the magnitude | size of the thrust bearing clearance gap between the bearing surface of the thrust bearing foil attached to each case member and the end surface of a flange part can be set with high precision, and the support precision of a thrust direction can be improved.

  For example, when the above-described foil bearing unit is incorporated in a turbo machine in which a turbine is driven by high-temperature gas, the foil bearing unit disposed near the turbine becomes high temperature. In this case, if a communication hole is provided to communicate the inner periphery and the outer periphery of the spacer, the fluid inside the bearing case can be discharged to the outside through the communication hole by centrifugal force accompanying the rotation of the flange portion. it can. As a result, high-temperature air inside the bearing case can be discharged and low-temperature air can be introduced from the outside, so that the air inside the bearing case, and thus the foil bearing unit itself can be cooled. In particular, if a communication path that connects the radial bearing gap and the outside is formed between the inner peripheral surface of the sleeve portion and the outer peripheral surface of the rotary shaft fixed to the inner peripheral surface, the external air is It can be positively introduced into the radial bearing gap, increasing the cooling effect.

  In the foil bearing unit described above, another radial bearing foil is attached to the inner peripheral surface of the second case member, and a fluid generated in a radial bearing gap between the outer peripheral surface of the shaft portion and the bearing surface of the other radial bearing foil. The inner member can be supported in the radial direction by pressure. Thereby, since the radial bearing gap is provided on both axial sides of the flange portion, the inner member can be stably supported even when the flange portion has a large diameter.

  An attachment member provided on an outer periphery of the first case member; and an attenuation member that connects the first case member and the attachment member. The deformation of the attenuation member causes the first case member to be attached to the attachment member. If the structure is allowed to move, vibration of the foil bearing unit can be absorbed by deformation of the damping material.

  As described above, according to the foil bearing unit of the present invention, the rotating shaft can be supported with high accuracy without causing an increase in manufacturing cost.

It is a figure which shows notionally the structure of a gas turbine. It is sectional drawing which shows the support structure of the rotor in the said gas turbine. It is sectional drawing of the foil bearing unit which concerns on one Embodiment of this invention integrated in the said support structure. It is a perspective view of the state which decomposed | disassembled the said foil bearing unit to the axial direction. It is sectional drawing in the AA of FIG. (A) is a perspective view of the foil which comprises a radial bearing foil, (B) is a perspective view of the state which formed the radial bearing foil by temporarily assembling three foils. It is a top view of the foil which comprises a thrust bearing foil. (A) is a top view of the end surface of a 1st case member, (B) is a top view of the end surface of a 2nd case member. It is sectional drawing in the B line | wire of FIG. (A) is a top view which shows two sets of foil groups which comprise a thrust bearing foil, (B) is a top view of a thrust bearing foil. It is an enlarged view of the C section of FIG. It is sectional drawing of the foil bearing unit which concerns on other embodiment. It is sectional drawing of the foil bearing unit which concerns on other embodiment. It is sectional drawing of the foil bearing unit which concerns on other embodiment. It is a side view which shows notionally the structure of a supercharger.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 conceptually shows the configuration of a gas turbine that is a kind of turbomachine. This gas turbine mainly includes a turbine 1 and a compressor 2 that form blade cascades, a generator 3, a combustor 4, and a regenerator 5. The turbine 1, the compressor 2, and the generator 3 are provided with a common rotating shaft 6 that extends in the horizontal direction, and the rotating shaft 6 and the turbine 1 and the compressor 2 constitute a rotor that can rotate integrally. . Air sucked from the intake port 7 is compressed by the compressor 2, heated by the regenerator 5, and then sent to the combustor 4. Fuel is mixed with this compressed air and burned, and the turbine 1 is rotated by high-temperature and high-pressure gas. The rotational force of the turbine 1 is transmitted to the generator 3 via the rotating shaft 6, and the generator 3 rotates to generate electric power, and this electric power is output via the inverter 8. Since the gas after rotating the turbine 1 is at a relatively high temperature, the heat of the gas after combustion is regenerated by sending this gas to the regenerator 5 and exchanging heat with the compressed air before combustion. Use. The gas that has been subjected to heat exchange in the regenerator 5 is discharged as exhaust gas after passing through the exhaust heat recovery device 9.

  2 to 4 show a foil bearing unit 100 that supports the rotating shaft 6 of the rotor in the gas turbine. The foil bearing unit 100 is fixed to the inner periphery of the housing 10 of the gas turbine. The foil bearing unit 100 includes an inner member 20 fixed to the rotary shaft 6, a bearing case 30 that houses the inner member 20, a radial bearing foil 40 and a thrust bearing foil 50 that are attached to the bearing case 30. .

  The inner member 20 includes a shaft portion (in this embodiment, a hollow sleeve portion 21) and a disk-like flange portion 22 that protrudes from the cylindrical outer peripheral surface 21a of the sleeve portion 21 to the outer diameter. In the present embodiment, the sleeve portion 21 and the flange portion 22 are integrally formed. For example, the sleeve portion 21 and the flange portion 22 are formed by cutting or forging the molten material, or by integrally forming with a sintered metal. In the example of illustration, the flange part 22 is provided in the axial direction edge part by the side of the compressor 2 of the sleeve part 21 (left side of FIG. 3). The outer peripheral surface of the rotating shaft 6 is fitted and fixed to the inner peripheral surface 21 b of the sleeve portion 21.

  The bearing case 30 includes a first case member 31 and a second case member 32. The first case member 31 is integrally provided with a cylindrical portion 31a and a flat plate portion 31b extending from the axial end of the cylindrical portion 31a on the compressor 2 side (left side in FIG. 3) to the outer diameter. In the example of illustration, the flat plate part 31b of the 1st case member 31 is comprised with the disk orthogonal to an axial direction. The second case member 32 includes a flat plate portion, and in the illustrated example, the second case member 32 is configured by a disk orthogonal to the axial direction. The first case member 31 is formed by cutting or forging the molten material, or by integrally forming with a sintered metal. A radial bearing foil 40 (indicated by a dotted line in FIG. 3) is attached to the inner peripheral surface 31c of the cylindrical portion 31a of the first case member 31. Thrust bearing foils 50 (shown by dotted lines in FIG. 3) are attached to the end surface 31d of the flat plate portion 31b of the first case member 31 and the end surface 32a of the second case member 32, respectively.

  As shown in FIG. 5, a groove 31 e for attaching the radial bearing foil 40 is formed on the inner peripheral surface 31 c of the cylindrical portion 31 a of the first case member 31. The grooves 31e extend over the entire length in the axial direction of the inner peripheral surface 31c of the cylindrical portion 31a, and are provided at a plurality of locations (three locations in the illustrated example) at equal intervals in the circumferential direction.

  The radial bearing foil 40 is composed of, for example, a plurality of (three in the illustrated example) foils 41. These foils 41 are attached to the inner peripheral surface 31c of the first case member 31 in a state of being arranged in the circumferential direction. The surface on the inner diameter side of each foil 41 functions as a radial bearing surface 41a. In the illustrated example, a multi-arc radial bearing surface is formed by three foils 41. A member (for example, a back foil) for imparting elasticity to the foil 41 is not provided between the inner peripheral surface 31c of the first case member 31 and each foil 41, and the outer diameter surface 41b of the foil 41 and The inner peripheral surface 31c of the first case member 31 directly faces in the radial direction.

  Each foil 41 is integrally formed by pressing one metal foil. As shown in FIG. 6A, each foil 41 includes a convex portion 41c provided at one end in the circumferential direction and a concave portion 41d provided at the other circumferential end. The convex portion 41c and the concave portion 41d of each foil 41 are provided at the same position in the axial direction. Thus, as shown in FIG. 6B, the three foils 41 can be temporarily assembled into a cylindrical shape by fitting the convex portions 41c of the foils 41 into the concave portions 41d of the adjacent foils 41. . As shown in FIG. 5, the convex portion 41 e at the other circumferential end of each foil 41 is inserted into a groove 31 e provided on the inner peripheral surface 31 c of the first case member 31. The convex portion 41 c at one circumferential end of each foil 41 is disposed between the outer diameter surface 41 b of the adjacent foil 41 and the inner peripheral surface 31 c of the first case member 31. As described above, both ends in the circumferential direction of each foil 41 are held in contact with the first case member 31.

  The thrust bearing foil 50 is composed of, for example, a plurality of foils 51, and is attached to the end surface 31d of the flat plate portion 31b of the first case member 31 and the end surface 32a of the second case member 32 by ring-shaped fixing members 33, respectively. (See FIGS. 3 and 4). As shown in FIG. 7, each foil 51 is integrally provided with a main body portion 51 a and a fixing portion 51 b that is fixed to the end surfaces 31 d and 32 a of the cases 31 and 32. The edge 51c on the rotation direction leading side and the edge 51d on the rear side in the rotation direction of the main body 51a are both substantially V-shaped with the central portion protruding toward the rotation direction leading side. The central part of each edge 51c, 51d is rounded in an arc shape. The fixing portion 51b of each foil 51 extends in a direction in which the outer diameter side is inclined rearward in the rotational direction (opposite to the arrow in FIG. 8). In each thrust bearing foil 50, the fixing portions 51 b of the plurality of foils 51 are arranged on the same circumference, and are sandwiched and fixed by the ring-shaped fixing member 33 and the end surfaces 31 d and 32 a of the case members 31 and 32.

  As shown in FIGS. 8A and 8B, the plurality of foils 51 constituting the thrust bearing foil 50 are arranged on the end surface 31d of the first case member 31 and the end surface 32a of the second case member 32 in the circumferential direction or the like. Arranged on the pitch. As shown in FIG. 9, the edge 51 c on the rotation direction leading side of each foil 51 is arranged on the adjacent foil 51 (on the flange portion 22 side). That is, the rotation direction leading side portion of each foil 51 rides on the rotation direction rear side portion of the adjacent foil 51. Of each of the foils 51, a portion (a portion visible in FIG. 8) that directly faces the end surfaces 22a and 22b of the flange portion 22 functions as a thrust bearing surface 51e.

  The foils 41 and 51 are formed of a metal foil having a thickness of approximately 20 μm to 200 μm made of a metal having a high spring property and good workability, such as a steel material or a copper alloy. In an air dynamic pressure bearing using air as a fluid film as in the present embodiment, since no lubricating oil exists in the atmosphere, the antirust effect by the oil cannot be expected. Typical examples of steel materials and copper alloys include carbon steel and brass, but general carbon steel is susceptible to corrosion due to rust, and brass may cause cracks due to processing strain (in brass) This tendency increases as the Zn content increases.) Therefore, it is preferable to use a metal foil made of stainless steel or bronze.

  The foil bearing unit 100 having the above configuration is assembled in the following procedure.

  First, the radial bearing foil 40 is temporarily assembled {see FIG. 6 (B)} and attached to the inner peripheral surface 31 c of the first case member 31. Specifically, the radial bearing foil 40 is inserted into the groove 31e provided on the inner peripheral surface 31c of the first case member 31 from one side in the axial direction while inserting the projection 41e of each foil 41 of the temporarily assembled radial bearing foil 40. 40 is inserted into the inner periphery of the first case member 31.

  Then, the thrust bearing foil 50 is attached to the end surface 31 d of the first case member 31 and the end surface 32 a of the second case member 32. Specifically, first, as shown in FIG. 10 (A), two sets of foil groups composed of a plurality of foils 51 obtained by cutting one metal foil are prepared (in FIG. 10, easy to understand). As you can see, one foil group is dotted.) The two sets of foils are overlapped by shifting the phase by half of each foil {see FIG. 10B}, and the leading edge 51c of each foil 51 is overlapped on the adjacent foil 51. In this state, the thrust bearing foil 50 is fixed to the first case member 31 by sandwiching the fixing portion 51b of each foil 51 between the end surface 31d of the flat plate portion 31b of the first case member 31 and the ring-shaped fixing member 33. It is attached {see FIG. 8 (A)}. Similarly, the thrust bearing foil 50 is attached to the second case member 32 by sandwiching the fixing portion 51b of each foil 51 between the end surface 32a of the second case member 32 and the ring-shaped fixing member 33 {FIG. (See (B)). The fixing portion 51b of the foil 51 may be bonded or welded to the end surface 31d of the flat plate portion 31b of the first case member 31, the end surface 32a of the second case member 32, or the ring-shaped fixing member 33.

  Next, the sleeve portion 21 of the inner member 20 is inserted into the inner periphery of the radial bearing foil 40 attached to the first case member 31. Thereafter, the second case member 32 is attached to the first case member 31 so as to sandwich the flange portion 22 of the inner member 20 from both sides in the axial direction. Specifically, the fixing member 33 attached to the first case member 31 and the fixing member 33 attached to the second case member 32 are brought into contact with each other, and in this state, the case members 31 and 32 are connected with bolts (not shown). Fix in the axial direction. At this time, as shown in FIG. 3, the common positioning pins 34 are fitted into the axial holes provided in the both fixing members 33, thereby positioning the both fixing members 33 in the direction perpendicular to the axis, and thus both the case members. Positioning in the direction orthogonal to the axes 31 and 32 is performed.

  Thus, the foil bearing unit 100 is completed. The foil bearing unit 100 has a bearing case 30 in which the inner member 20 is housed, and the first case member 31, the second case member 32, and the flange portion 22 are engaged in the axial direction, thereby bearings. The inner member 20 is prevented from coming off from the case 30. Thereby, since the foil bearing unit 100 can be handled integrally, the assembly property to the housing 10 to a gas turbine improves.

  In the above configuration, when the rotary shaft 6 is rotated in one circumferential direction (the arrow direction in FIGS. 5 and 8), the bearing surface 41a of the radial bearing foil 40 and the outer peripheral surface 21a of the sleeve portion 21 of the inner member 20 An air film is formed in the gap between the radial bearings, and the inner member 20 and the rotating shaft 6 are supported in the radial direction by the pressure of the air film. At the same time, the thrust bearing gap between the bearing surface 51e of the thrust bearing foil 50 attached to the first case member 31 and the one end surface 22a of the flange portion 22 of the inner member 20, and the second case member 32 An air film is formed in each of the thrust bearing gaps between the bearing surface 51e of the thrust bearing foil 50 attached to the inner surface 20 and the other end surface 22b of the flange portion 22 of the inner member 20. The inner member 20 and the rotating shaft 6 are supported in both thrust directions by the pressure of the air film.

  Further, when the rotating shaft 6 rotates, the foils 41 of the radial bearing foil 40 try to rotate in the rotation direction leading side (arrow direction in FIG. 5) due to friction with the rotating shaft 6 and air viscosity. At this time, the movement of each foil 41 is restricted by the end portion (convex portion 41e) on the leading side in the rotation direction of each foil striking the corner portion of the groove 31e. As a result, as shown in FIG. 11, the end portion (convex portion 41e) in the rotational direction leading side of each foil 41 is curved inside the groove 31e, and the bearing surface 41a is curved so as to be convex toward the inner diameter side. When the pressure of the air film in the radial bearing gap increases, the foils 41 of the radial bearing foil 40 are pushed into the outer diameter side and elastically deformed. The shape of the foil 41 is maintained at a position where the elastic force of the foil 41 at this time and the pressure of the air film formed in the radial bearing gap are balanced. Further, when the pressure of the air film in the thrust bearing gap increases as the rotating shaft 6 rotates, the foils 51 of the thrust bearing foil 50 are pushed into the first and second case members 31 and 32 and elastically deformed ( (See FIG. 9). The shape of the foil 51 is maintained at a position where the elastic force of the foil 51 at this time and the pressure of the air film formed in the thrust bearing gap are balanced.

  At this time, due to the flexibility of the foils 41 and 51, the bearing surfaces 41a and 51e of the foils 41 and 51 are arbitrarily deformed according to the operating conditions such as the load, the rotational speed of the rotary shaft 6, and the ambient temperature. The radial bearing gap and the thrust bearing gap are automatically adjusted to appropriate widths according to the operating conditions. Therefore, the radial bearing gap and the thrust bearing gap can be managed to the optimum width even under severe conditions such as high temperature and high speed rotation, and the inner member 20 and the rotating shaft 6 can be stably supported.

  Further, by attaching the radial bearing foil 40 and one thrust bearing foil 50 to the integrally formed first case member 31, the mounting surfaces to which the bearing foils 40, 50 are attached (the inner peripheral surface 31c of the cylindrical portion 31a and The relative positional accuracy (perpendicularity etc.) of the end surface 31d) of the flat plate portion 31b can be set with high accuracy. As a result, the relative positional accuracy of the bearing surfaces 41a and 51e of the bearing foils 40 and 50, and consequently the radial bearing gap and the thrust bearing gap are set with high accuracy. Can be supported. In particular, in the present embodiment, since the sleeve portion 21 and the flange portion 22 of the inner member 20 are integrally formed, a surface (the sleeve portion 21) that faces the bearing foils 40 and 50 attached to the first case member 31. The relative positional accuracy of the outer peripheral surface 21a and the one end surface 22a) of the flange portion 22 is also set with high accuracy. Thereby, the precision of a radial bearing gap and a thrust bearing gap is further improved, and the support precision of the inner member 20 and the rotating shaft 6 is further improved.

  In the present embodiment, the fixing members 33 are provided between the first case member 31 and the second case member 32 in the axial direction. In this case, the fixing members 33 and 33 function as spacers that determine the axial distance between the end surface 31d of the first case member 31 and the end surface 32a of the second case member 32, and these axial distances are set with high accuracy. Is done. Thereby, the thrust bearing gap between the end surface 31d of the first case member 31 and one end surface 22a of the flange portion 22 of the inner member 20, and the end surface 32a of the second case member 32 and the flange of the inner member 20 are obtained. It becomes possible to set the thrust bearing gap between the other end surface 22b of the portion 22 with high accuracy, and the support accuracy of the rotating shaft 6 in the thrust direction can be increased. In this embodiment, the fixing member 33 is provided in each of the first case member 31 and the second case member 32. However, the fixing portion 51b of the foil 51 is replaced with the end surface 31d of the flat plate portion 31b of the first case member 31 and the first case member 31. When the end surfaces 32a of the two case members 32 are joined together by a method such as welding, the number of the fixing members 33 may be one. In this case, the thrust bearing clearance can be determined only by the axial dimension of one fixed member 33.

  It should be noted that the bearing surfaces 41a and 51e of the foils 41 and 51 and the inner member 20 slide in contact with each other at the time of low speed rotation immediately before the rotation shaft 6 is stopped or immediately after starting. Alternatively, a low friction coating such as a titanium aluminum nitride film or a molybdenum disulfide film may be formed. Further, during the operation of the bearing, minute sliding occurs between the foils 41 and 51 and the case members 31 and 32. Therefore, the above-described low friction coating is formed on one or both of them. May be.

  The present invention is not limited to the above embodiment. In the embodiment shown in FIG. 12, the fixing member 33 is provided with a communication hole 33a in the radial direction. Thereby, with rotation of the rotating shaft 6 and the inner member 20, the air in the thrust bearing gap flows toward the outer diameter side by centrifugal force and is discharged to the outside from the communication hole 33a. At this time, the air in the thrust bearing gap between the first case member 31 and the flange portion 22 is discharged to the outside from the communication hole 33a, so that the air in the radial bearing gap communicated with the air passes through the thrust bearing gap. It is discharged to the outside from the communication hole 33a. Since the foil bearing unit 100 has a high temperature on the turbine 1 side, the air inside the bearing case 30 can be cooled by discharging the air in the radial bearing gap close to the turbine 1 to the outside.

  In the present embodiment, a communication path 60 is provided that communicates the end of the radial bearing gap on the turbine side with the space on the compressor 2 side of the foil bearing unit 100. Specifically, the axial groove 21c is provided on the inner peripheral surface 21b of the inner member 20, and the radial groove 21d is provided on the end surface of the inner member 20 on the turbine 1 side. The communication path 60 is formed by the groove 21d. As a result, the air in the thrust bearing gap is discharged to the outside through the communication hole 33a due to the rotation of the rotary shaft 6, so that the air on the compressor 2 side becomes the end of the radial bearing gap on the turbine 1 side via the communication path 60. Introduced from the department. Since the air on the compressor 2 side is much lower in temperature than the air on the turbine 1 side, the foil bearing unit 100 can be efficiently cooled by introducing the air on the compressor 2 side into the radial bearing gap. It becomes possible.

  In the embodiment shown in FIG. 13, the attachment member 70 is provided on the outer periphery of the bearing case 30, and these are connected via the damping material 80. The outer peripheral surface of the attachment member 70 is attached to the housing 10 of the gas turbine. In the illustrated example, the mounting member 70 has a cylindrical shape, and the inner peripheral surface 71 of the mounting member 70 and the outer peripheral surface 31 f of the bearing case 30 are connected via a damping material 80. As the damping material 80, for example, a wire mesh, high viscosity oil, resin, rubber, or the like can be used. An O-ring 90 is disposed between the mounting member 70 and the bearing case 30. The O-ring 90 restricts the radial movement of the bearing case 30 with respect to the mounting member 70. The bearing case 30 is allowed to move in the circumferential direction and the axial direction with respect to the mounting member 70 by deforming the damping member 80. Thereby, when vibration occurs in the bearing case 30, the vibration can be damped by absorbing the vibration of the bearing case 30 by the deformation of the damping material 80.

  In the embodiment shown in FIG. 14, the flange portion 22 is provided in the intermediate portion in the axial direction (in the illustrated example, the central portion in the axial direction) of the sleeve portion 21 of the inner member 20, and the cylindrical portion 32 b and the second case member 32 are provided. A disk-shaped flat plate portion 32c is provided integrally. A radial bearing foil 40 is attached to the inner peripheral surface 32 d of the cylindrical portion 32 b of the second case member 32. Thereby, since the radial bearing gap is provided on both axial sides of the flange portion 22, it is possible to increase the support force against the moment force accompanying the swing of the rotating shaft 6. In particular, when the diameter of the flange portion 22 is increased (for example, when the diameter of the flange portion 22 is larger than the length in the axial direction of the sleeve portion 21), the moment force increases, so the configuration of the present embodiment is effective. It becomes.

  Although the case where the radial bearing foil 40 is configured by a multi-arc bearing has been described in the above embodiment, the present invention is not limited thereto, and one end in the circumferential direction of each foil is attached to the inner peripheral surface of the bearing case 30, and the circumference of each foil is A so-called leaf-type radial bearing foil having the other end in the direction as a free end, or a so-called bump foil-type radial bearing foil in which a corrugated back foil is arranged on the outer diameter of a cylindrical top foil may be used. .

  Moreover, although the thrust bearing foil 50 showed the case where the fixing | fixed part 51b provided in the outer-diameter end of each foil 51 was fixed to the bearing case 30 in the above embodiment, it is not restricted to this, Each foil 51 of each foil 51 is shown. One end in the circumferential direction may be attached to the bearing case 30 and the other end in the circumferential direction may be a free end.

  The application object of the foil bearing unit 100 according to the present invention is not limited to the gas turbine described above, and can be used as a bearing for supporting a rotor of a supercharger, for example. As shown in FIG. 15, the supercharger drives the turbine 101 with exhaust gas generated in the engine 103, rotates the compressor 102 with the driving force to compress the intake air, and increases the torque and efficiency of the engine 103. It is intended to improve. The turbine 101, the compressor 102, and the rotating shaft 6 constitute a rotor, and the foil bearing unit 100 of each of the above embodiments can be used as a bearing that supports the rotating shaft 6.

  The foil bearing according to the present invention is not limited to a turbo machine such as a gas turbine or a supercharger, and a lubricating oil circulation system auxiliary machine is provided separately from the viewpoint of energy efficiency, which is difficult to lubricate with a liquid such as lubricating oil. Therefore, it can be used widely as a bearing for vehicles such as automobiles, which is used under the restriction that resistance due to shearing of liquid becomes a problem, and for industrial equipment.

  Each of the foil bearings described above is an air dynamic pressure bearing that uses air as a pressure generating fluid. However, the present invention is not limited to this, and other gases can be used as the pressure generating fluid, or water or oil can be used. A liquid such as can also be used.

DESCRIPTION OF SYMBOLS 1 Turbine 2 Compressor 6 Rotating shaft 10 Housing 20 Inner member 21 Sleeve part 22 Flange part 30 Bearing case 31 First case member 32 Second case member 33 Fixed member 40 Radial bearing foil 41 Foil 50 Thrust bearing foil 51 Foil 60 Continuous Passage 70 Mounting member 80 Damping material 100 Foil bearing unit

Claims (7)

A first case member integrally having a cylindrical portion and a flat plate portion extending from the cylindrical portion to an outer diameter, a second case member having a flat plate portion attached to the first case member, and a cylindrical portion of the first case member A radial bearing foil directly attached to the inner peripheral surface of the first case member, a thrust bearing foil directly attached to the end surface of the flat plate portion of the first case member, and another attached to the end surface of the flat plate portion of the second case member A thrust bearing foil, a hollow sleeve portion that is inserted into the inner periphery of the cylindrical portion of the first case member, and a rotation shaft is fitted and fixed to the inner peripheral surface , and a flange portion that protrudes from the sleeve portion to the outer diameter and a inner member having, for supporting the inner member with a fluid pressure generated in the radial bearing gap between the bearing surface and the outer peripheral surface of the sleeve portion of the radial bearing foil in the radial direction Both thrust bearing gap between the bearing surface and the end surface of the flange portion of the thrust bearing foil, and a thrust bearing gap between the end surface of the flange portion and the bearing surface of the other thrust bearing foil A foil bearing unit that supports the inner member in the thrust direction with the generated fluid pressure.   The foil bearing unit according to claim 1, wherein the sleeve portion and the flange portion are integrally formed. Foil bearing unit according to claim 1, wherein the spacer is provided axially between the second casing member and the first case member. The foil bearing unit according to claim 3, wherein a communication hole that communicates the inner periphery and the outer periphery of the spacer is provided. The foil bearing according to claim 4 , wherein a communication path is formed between the inner peripheral surface of the sleeve portion and the outer peripheral surface of the rotary shaft fixed to the inner peripheral surface to communicate the radial bearing gap with the outside. unit. The second case member further includes a cylindrical portion, and another radial bearing foil is attached to the inner peripheral surface of the cylindrical portion of the second case member, and the outer peripheral surface of the shaft portion of the inner member and the other radial bearing foil The foil bearing unit according to any one of claims 1 to 5 , wherein the inner member is supported in a radial direction by a fluid pressure generated in a radial bearing gap between the inner bearing surface and the bearing surface. An attachment member provided on an outer periphery of the first case member; and an attenuation member that connects the first case member and the attachment member. The deformation of the attenuation member causes the first case member to be attached to the attachment member. The foil bearing unit according to any one of claims 1 to 6 , wherein said movement is allowed.

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