JP6104597B2 - Foil bearing - Google Patents

Foil bearing Download PDF

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JP6104597B2
JP6104597B2 JP2012276907A JP2012276907A JP6104597B2 JP 6104597 B2 JP6104597 B2 JP 6104597B2 JP 2012276907 A JP2012276907 A JP 2012276907A JP 2012276907 A JP2012276907 A JP 2012276907A JP 6104597 B2 JP6104597 B2 JP 6104597B2
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foil
circumferential
bearing
peripheral
holding
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JP2014119095A (en
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真人 吉野
真人 吉野
藤原 宏樹
宏樹 藤原
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Ntn株式会社
Ntn株式会社
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Description

  The present invention relates to a foil bearing.

  The main shaft of a gas turbine or turbocharger is driven to rotate at high speed. Moreover, the turbine blade attached to the main shaft is exposed to high temperature. Therefore, bearings that support these main shafts are required to be able to withstand severe environments such as high temperature and high speed rotation. Oil lubricated rolling bearings and hydrodynamic pressure bearings may be used as bearings for this type of application, but if lubrication with a liquid such as lubricating oil is difficult, the auxiliary equipment of the lubricating oil circulation system from the viewpoint of energy efficiency The use of these bearings is restricted under conditions such as when it is difficult to provide a separate or when resistance due to liquid shear becomes a problem. Therefore, an air dynamic pressure bearing has attracted attention as a bearing suitable for use under such conditions.

  As an air dynamic pressure bearing, one in which both the rotating side and the fixed side bearing surfaces are made of a rigid body is generally used. However, in this type of air dynamic pressure bearing, if the radial bearing clearance formed between the rotating and stationary bearing surfaces is insufficiently managed, a self-excited so-called whirl is called when the stability limit is exceeded. It is easy for the spindle to run out. Therefore, gap management according to the rotation speed used is important. In particular, in an environment such as a gas turbine or a turbocharger where the temperature changes drastically, the radial bearing gap varies due to the effect of thermal expansion, so accurate gap management becomes extremely difficult.

  A foil bearing is known as a bearing that is less likely to cause a whirl and can easily manage a gap even in an environment with a large temperature change. 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. Normally, the inner peripheral surface of the bearing is composed of a thin plate called a top foil, and a spring-like member called a back foil is arranged on the outer diameter side to elastically support the load received by the top foil with the back foil. Yes. In this case, when the shaft rotates, an air film is formed between the outer peripheral surface of the shaft and the inner peripheral surface of the top foil, and the shaft is supported in a non-contact manner.

  Foil bearings are characterized by excellent stability because of the flexibility of the foil, an appropriate radial bearing gap is formed according to the operating conditions such as shaft rotation speed, load, and ambient temperature. It can be used at a higher speed than an air dynamic pressure bearing. In addition, the radial bearing clearance of a general dynamic pressure bearing needs to be managed in the order of 1/1000 of the shaft diameter. For example, a radial bearing clearance of about several μm needs to be always secured for a shaft having a diameter of about several millimeters. . Therefore, when taking into account manufacturing tolerances, and even thermal expansion when the temperature change is severe, strict gap management is difficult. On the other hand, in the case of a foil bearing, it is sufficient to manage a radial bearing gap of about several tens of μm, and there is an advantage that its manufacture and gap management become easy.

  As the foil bearing, a top foil is elastically supported by a cut and raised provided in a back foil (Patent Document 1), and a bearing foil is elastically supported by an elastic body formed by meshing strands (Patent Document). 2) and those having a back foil provided with a support portion that contacts the inner surface of the outer ring and does not move in the circumferential direction and an elastic portion that is elastically bent by the surface pressure from the top foil (Patent Document 3), etc. are known. is there. Patent Documents 4 and 5 show so-called multi-arc type foil bearings in which a plurality of foils are arranged side by side in the circumferential direction, and both circumferential ends of each foil are attached to an outer member.

JP 2002-364463 A JP 2003-262222 A JP 2009-299748 A JP 2009-216239 A JP 2006-57828 A

  In the multi-arc type foil bearings disclosed in Patent Documents 4 and 5 described above, protrusions protruding toward the inner diameter (displacement suppressing portions, engagement members) are provided at a plurality of locations spaced in the circumferential direction of the inner peripheral surface of the outer member. Stop mechanism), and the foil is fixed between the circumferential directions of the projecting portions. However, in this case, since the inner diameter surface of the projecting portion is exposed from between the circumferential directions of the foils, the area of the bearing surface is reduced by the amount of the projecting portion, which may cause a reduction in support force.

  Therefore, an object of the present invention is to provide a multi-arc type foil bearing capable of attaching a foil to an outer member without reducing the area of the bearing surface.

  To achieve the above object, the present invention includes an outer member having a cylindrical inner peripheral surface, and a plurality of foils attached to the inner peripheral surface of the outer member, and is inserted into the inner periphery. A foil bearing that supports a shaft in a radial direction so as to be relatively rotatable, and each foil has a bearing surface and is held in a state in which both end portions in the circumferential direction are in contact with the outer member. The circumferential ends are crossed in the axial direction, and the circumferential ends of the foils are arranged on the outer diameter side of the adjacent foils.

  In this way, the circumferential ends of the adjacent foils are crossed in the axial direction, and the circumferential ends of the foils are arranged on the outer diameter side of the adjacent foils, so that on the back side (outer diameter side) of the foil The circumferential end of each foil can be held on the inner circumferential surface of the outer member. Thereby, since foil can be continuously arrange | positioned in the circumferential direction and the inner peripheral surface whole periphery of an outer member can be covered with foil, the reduction | decrease in the area of a bearing surface can be avoided.

  For example, each foil can be attached to the outer member by inserting both ends in the circumferential direction of each foil into a fixing groove provided on the inner peripheral surface of the outer member. Alternatively, one end in the circumferential direction of each foil is inserted into a fixing groove provided on the inner peripheral surface of the outer member, and the other end in the circumferential direction of each foil is inserted into the inner side of the adjacent foil and the outer member. Each foil can be attached to the outer member by being arranged between the peripheral surface.

  If at least one end in the circumferential direction of each foil is slidable with respect to the outer member, vibration due to relative rotation of the shaft can be attenuated by frictional energy of sliding between the foil and the outer member. .

  For example, a convex part formed by extending a partial axial direction region is provided at one end in the circumferential direction of each foil, and an axial region different from the convex part is extended at the other circumferential end of each foil. Providing the projecting portions that are present allows the projecting portions provided at the ends of the adjacent foils to intersect in the axial direction. Alternatively, a convex portion is formed by extending a partial region in the axial direction at one end portion in the circumferential direction of each foil, a slit is provided at the other end portion in the circumferential direction of each foil, and the convex portions are adjacent to each other. If it inserts into the said slit of foil, the edge part of an adjacent foil can be made to cross | intersect by an axial view. In these cases, each foil is held in a balanced manner in the axial direction by providing convex portions at a plurality of locations separated in the axial direction at one end in the circumferential direction of each foil and attaching the convex portions to the outer member. Can do.

  The foil bearing described above can be configured, for example, by providing an elastic member (for example, a back foil) that imparts elasticity toward the inner diameter of each foil between each foil and the inner peripheral surface of the outer member.

  As described above, according to the present invention, it is possible to obtain a multi-arc type foil bearing capable of attaching a foil to an outer member without reducing the area of the bearing surface.

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 the front view which looked at the foil bearing concerning one Embodiment of this invention from the axial direction. (A) is a perspective view of the foil used with the said foil bearing, (b) is a perspective view which shows the state which combined multiple foils. (A) is a perspective view of the back foil used by the foil bearing of FIG. 3, (b) is a perspective view which shows the state which combined multiple back foils. It is an expanded sectional view of the foil bearing. (A) is a perspective view of the foil used with the foil bearing which concerns on other embodiment, (b) is a perspective view which shows the state which combined multiple foils. It is an expanded sectional view of the foil bearing which concerns on other embodiment. (A) is a perspective view of the foil used with the foil bearing which concerns on other embodiment, (b) is a perspective view which shows the state which combined multiple foils. 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 the gas turbine. 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 shaft 6 that extends in the horizontal direction, and the shaft 6, 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 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.

  FIG. 2 shows an example of a support structure for the rotor in the gas turbine. In this support structure, radial bearings 10 are disposed at two axial positions, and thrust bearings 20 and 20 are disposed on both axial sides of the flange portion 6 b of the shaft 6. The shaft 6 is supported by the radial bearing 10 and the thrust bearing 20 so as to be rotatable in the radial direction and in both thrust directions.

  In this support structure, the region between the turbine 1 and the compressor 2 is adjacent to the turbine 1 that is rotated by high-temperature, high-pressure gas, and therefore has a high-temperature atmosphere. In this high temperature atmosphere, the lubricant composed of lubricating oil, grease and the like is altered and evaporated, so it is difficult to apply a normal bearing (such as a rolling bearing) using these lubricants. Therefore, as the bearings 10 and 20 used in this type of support structure, an air dynamic pressure bearing, particularly a foil bearing is suitable.

  Hereinafter, the structure of the foil bearing 10 suitable for the radial bearing for the gas turbine will be described with reference to the drawings.

  As shown in FIG. 3, the foil bearing 10 is fixed to an inner periphery of a housing (not shown), and an outer member 11 into which the shaft 6 is inserted and an inner peripheral surface 11 a of the outer member 11. A plurality of attached foils 13 (top foil) and an elastic member provided between the inner peripheral surface 11a of the outer member 11 and the foil 13 for imparting elasticity to the foil 13 are configured. In this embodiment, the case where the elastic member is the back foil 12 is shown. The foil bearing 10 is a so-called multi-arc type foil bearing in which the inner peripheral surface 11a of the outer member 11 has a cylindrical surface shape, and three foils 13 are arranged in the circumferential direction on the inner peripheral surface 11a. is there.

  Each foil 13 includes a holding portion 13a, 13b provided at both ends in the circumferential direction and a main body portion 13c provided between the holding portions 13a, 13b in the circumferential direction. Each foil 13 including the holding portions 13a and 13b and the main body portion 13c is integrally formed from a single foil by pressing or the like. The holding portions 13 a and 13 b are held in contact with the outer member 11. The end portions in the circumferential direction of the adjacent foils 13 (in the present embodiment, holding portions 13a and 13b) are provided so as to cross each other when viewed in the axial direction (see FIG. 3), and the holding portions 13a and 13b of each foil 10 are adjacent to each other. The main body 13c of the foil 10 is arranged on the outer diameter side. In the illustrated example, the holding portions 13 a and 13 b are inserted into the fixing grooves 11 b and 11 c provided on the inner peripheral surface 11 a of the outer member 11. The fixing grooves 11b and 11c are formed by wire cutting, for example, and are formed over the entire axial length of the outer member 11. At least one of the holding portions 13a and 13b is not completely fixed to the fixing grooves 11b and 11c, and is held in a slidable state. The fixed groove 11b is inclined in one circumferential direction toward the outer diameter (see the arrow in FIG. 3), and the fixed groove 11c is inclined in the other circumferential direction toward the outer diameter. The fixing grooves 11b and 11c are opened at the same circumferential position. The body 13c of the foil 13 is formed by bending a rectangular flat plate into a substantially arc shape, and has a bearing surface A on the inner diameter surface 13c2.

  As shown in FIG. 4 (a), one holding portion 13a in the circumferential direction of each foil 13 extends a partial region in the axial direction of the main body portion 13c (in the illustrated example, the central portion in the axial direction) to one circumferential direction. Consists of convex parts. On the other hand, the other holding portion 13b in the circumferential direction of each foil 13 is formed by a convex portion in which a part in the axial direction of the main body portion 13c extends in the other circumferential direction. The other holding portion 13b in the circumferential direction is composed of a plurality of (two in the illustrated example) convex portions that are spaced apart in the axial direction, and a concave portion 13b1 is provided between these axial directions. By inserting the holding portion 13a provided at one end of the foil 13 into the recess 13b1 between the holding portions 13b provided at the other end of the adjacent foil, the holding portions 13a and 13b intersect in the axial direction (see FIG. 4 (b)).

  As shown in FIG. 4 (b), one holding portion 13a of the foil 13 is inserted into the recess 13b1 provided between the axial directions of the other holding portion 13b of the foil 13 adjacent thereto, and a plurality of (illustrated examples) are inserted. The three foils 13 are attached to the inner peripheral surface 11a of the outer member 11 by inserting the holding portions 13a and 13b into the fixing grooves 11b and 11c, respectively. In this way, by holding the holding portions 13a and 13b of the adjacent foils 13 and inserting them into the fixing grooves 11b and 11c on the outer diameter side (back side) of the foil 13, the entire circumference of the inner peripheral surface 11a of the outer member 11 is obtained. Can be covered with the main body 13c of the foil 13, the area of the bearing surface can be ensured to the maximum. Further, since the circumferential end portions (holding portions 13a and 13b) of the foil 13 are not exposed on the sliding surface with the shaft 6, it is possible to reliably prevent the circumferential end portion of the foil 13 from turning to the inner diameter side.

  As shown in FIG. 5A, each back foil 12 has substantially the same shape as the foil 13, and the holding portions 12a and 12b provided at both ends in the circumferential direction, and between the holding portions 12a and 12b in the circumferential direction. And a main body 12c provided on the main body 12c. The holding portions 12a and 12b are substantially flat, and the main body portion 12c has a shape that can be elastically deformed by a compressive force in the radial direction. In the present embodiment, the main body portion 12c has a corrugated shape, and the height of the unevenness gradually decreases from the circumferential central portion of the main body portion 12c toward both ends. As with the foil 13, the back foil 12 can be inserted between a pair of holding portions 12b provided at one end of a holding portion 12a provided at one end (FIG. 5B). reference).

  As shown in FIG. 6, both ends in the circumferential direction of the body portion 13c of each foil 13 (boundary portions with the holding portions 13a and 13b) do not extend along the inner peripheral surface 11a of the outer member 11, With respect to the inner peripheral surface 11a, the main body portion 13c rises toward the inner diameter side toward the center in the circumferential direction. In the illustrated example, the boundary between the circumferential ends of the main body portion 13c and the holding portions 13a and 13b is smoothly continuous without being bent, and the circumferential end portion of the main body portion 13c is curved so as to protrude toward the inner diameter. doing. If the rising angles θ1 and θ2 of the main body portion 13c of the foil 13 are too large, the foil 13 is greatly pushed out toward the inner diameter side, so that the possibility of bending due to interference with the shaft 6 increases. Therefore, it is desirable to set the rising angles θ1 and θ2 to 30 ° or less, preferably 20 ° or less. The rising angles θ1 and θ2 may be the same or different. In the illustrated example, θ1> θ2.

  The foil 13 is formed of a strip-like foil having a thickness of about 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 stainless steel or bronze foil as the belt-like foil.

  The assembly of the foil bearing 10 is performed as follows. First, the foil 13 (refer FIG. 4) and the back foil 12 (refer FIG. 5) of substantially the same shape are piled up, and three sets are prepared. Then, the holding portions 13a and 12a at one end of the overlapped foil 13 and the back foil 12 are inserted between a pair of holding portions 13b and 12b provided at the other end of the other foil 13 and the back foil 12, and three sets of The foil 13 and the back foil 12 are connected in an annular shape. In this state, the foil 13 and the back foil 12 are inserted into the fixing grooves 11 b and 11 c of the outer member 11 by inserting the one holding portion 13 a and 12 a and the other holding portion 13 b and 12 b of each foil 13 and the back foil 12. 12 is attached to the inner peripheral surface of the outer member 11.

  In the above configuration, when the shaft 6 is rotated in one circumferential direction (the direction of the arrow in FIG. 3), that is, in the reduction direction of the wedge-shaped radial bearing gap R, the bearing surface A of each foil 13 and the outer peripheral surface 6a of the shaft 6 An air film is formed between them. When the pressure of the air film increases, the end of the main body 13c of the foil 13 is pushed into the outer diameter side, and the back foil 12 is elastically deformed and compressed in the radial direction. A wedge-shaped radial bearing gap R is formed at a plurality of circumferential locations around the shaft 6 (three locations in the illustrated example), and the shaft 6 is supported so as to be rotatable in the radial direction in a non-contact state with respect to the foil 13. The At this time, the shape of the foil 13 and the back foil 12 is maintained at a position where the elastic force of the back foil 12 and the pressure of the air film formed in the radial bearing gap R are balanced. The actual radial bearing gap R has a very small width of about several tens of μm, but in FIG. 3, the width is exaggerated. Further, due to the flexibility of the foil 13 and the back foil 12, the bearing surface A of each foil 13 is arbitrarily deformed according to the operating conditions such as the load, the rotational speed of the shaft 6, the ambient temperature, etc. Is automatically adjusted to an appropriate width according to the operating conditions. Therefore, the radial bearing gap R can be managed to the optimum width even under severe conditions such as high temperature and high speed rotation, and the shaft 6 can be stably supported.

  In the foil bearing 10, it is difficult to form an air film having a thickness equal to or greater than the surface roughness on the bearing surface A of each foil 13 and the outer peripheral surface 6 a of the shaft 6 at the time of low-speed rotation immediately before the shaft 6 is stopped or immediately after starting. Become. Therefore, a metal contact is produced between the bearing surface A of each foil 13 and the outer peripheral surface 6a of the shaft 6, thereby causing an increase in torque. In order to reduce the torque by reducing the frictional force at this time, the bearing surface A (inner diameter surface 13c2) of each foil 13 and the surface of the sliding member (in this embodiment, the outer peripheral surface 6a of the shaft 6). It is desirable to form a coating (first coating) that reduces the surface friction on either or both. As this coating, for example, a DLC film, a titanium aluminum nitride film, or a molybdenum disulfide film can be used. The DLC film, titanium or aluminum nitride film can be formed by CVD or PVD, and the molybdenum disulfide film can be easily formed by spraying. In particular, since the DLC film and the titanium aluminum nitride film are hard, by forming a film with them, the wear resistance of the bearing surface A can be improved, and the bearing life can be increased.

  Further, during the operation of the bearing, the foil 13 and the back foil 12 are entirely expanded by the influence of the air film formed in the radial bearing gap and are pressed against the inner peripheral surface 11a of the outer member 11, and accordingly Between the outer diameter surface 13c1 of the foil 13 and the inner diameter surface of the back foil 12, between the outer diameter surface of the back foil 12 and the inner peripheral surface 11a of the outer member 11, and the holding of the foil 13 and the back foil 12. Minute sliding in the circumferential direction occurs between the portions 13a, 13b, 12a, 12b and the fixing grooves 11b, 11c. Therefore, either or both of the outer diameter surface 13c1 of the foil 13 and the inner diameter surface of the back foil 12 that contacts this, the outer diameter surface of the back foil 12, and the inner peripheral surface 11a of the outer member 11 that contacts this. One or both of them, one or both of the holding portions 13a and 13b of the foil 13 and the fixing grooves 11b and 11c that contact with the holding portions 13a and 13b, or the holding portions 12a and 12b of the back foil 12 and the fixing that comes into contact with this. By forming a coating (second coating) on one or both of the grooves 11b and 11c, it is possible to improve wear resistance at these sliding portions.

  In order to improve the vibration damping action, a certain amount of frictional force may be required at the sliding portion, and the second coating is not required to have very low friction. Therefore, it is preferable to use a DLC film or a titanium aluminum nitride film having a higher friction coefficient than that of the bifurcated molybdenum film but excellent in wear resistance as the second film. For example, a molybdenum disulfide film is used as the first coating formed on the bearing surface A, while a titanium aluminum nitride or DLC film is used as the second coating formed on the sliding portion between the foil 13 and the outer member 11. By making the friction coefficients of the two coatings different, it is possible to achieve both a reduction in torque and an improvement in vibration damping.

  The present invention is not limited to the above embodiment. For example, the embodiment shown in FIG. 7 differs from the above-described embodiment in that a slit 13d is provided at the other end of the foil 13, more specifically, at the boundary between the main body portion 13c and the holding portion 13b on the other end side. The back foil 12 of the present embodiment is the same as the foil 13 of FIG. 7 except that the main body portion 12c is corrugated, and thus illustration and description thereof are omitted. The slit 13d is provided at the same axial position as the holding portion 13a on one end side of the foil 13, and the holding portion 13a can be inserted (see FIG. 7B). The holding portion 13a is inserted into the slit 13d of the adjacent foil 13, and the holding portions 13a and 13b of each foil 13 are inserted into the fixing grooves 11b and 11c of the outer member 11 in a state where the plurality of foils 13 are connected in a ring shape. Thus, the foil 13 is attached to the inner peripheral surface 11 a of the outer member 11. The axial cross section of the foil bearing 10 is in the same state as in FIG. In this case, since the holding portion 13a of the foil 13 passes through the slit 13d of the adjacent foil 13 and is inserted into the fixing groove 11b, the holding portion 13a and the slit 13d are engaged in the circumferential direction so that Movement of the end (holding portion 13b) in the circumferential direction is reliably restricted.

  In the embodiment shown in FIG. 8, the fixing groove 11 c is not provided in the outer member 11, and the holding portion 13 b on the other end side of the foil 13 is provided along the inner peripheral surface 11 a of the outer member 11. , Different from the above embodiment. The back foil 12 of the present embodiment is the same as the foil 13 of FIG. 8 except that the main body portion 12c is corrugated, and thus illustration and description thereof are omitted. Specifically, the holding portions 13a and 13b of the adjacent foils 13 are crossed when viewed in the axial direction (see FIG. 4 (b) or FIG. 7 (b)), and in this state, the holding portion 13a on one end side is moved outward. While being inserted into the fixing groove 11 b of the member 11, the holding portion 13 b on the other end side of the foil 13 is inserted between the adjacent foil 13 and the inner peripheral surface 11 a of the outer member 11. As a result, the holding portion 13 b on the other end side of the foil 13 is held from the inner diameter side by the adjacent foil 13 and is held in contact with the inner peripheral surface 11 a of the outer member 11.

  In this case, the movement of the foil 13 in one circumferential direction (the direction indicated by the solid arrow in FIG. 8) is restricted by the holding portion 13a hitting the inner part of the fixing groove 11b or by the slit hitting the holding portion 13a. The On the other hand, since the foil 13 is movable in the other circumferential direction (indicated by the dotted arrow in the figure), when the shaft 6 rotates in the other circumferential direction (in the direction indicated by the dotted arrow), the foil 13 is slid by sliding with the shaft 6. May move to the other circumferential direction, and the holding portion 13a on one end side of the foil 13 may come out of the fixing groove 11b. Therefore, this foil bearing 10 is used for the application which supports the axis | shaft 6 which rotates relatively only in the circumferential direction one side (solid arrow direction).

  The embodiment shown in FIG. 9 is different from the above-described embodiment in that the one holding portion 13a in the circumferential direction of the foil 13 is configured by a plurality of convex portions spaced apart in the axial direction. The back foil 12 of the present embodiment is the same as the foil 13 of FIG. 9 except that the main body 12c is corrugated, and thus illustration and description thereof are omitted. In this way, by inserting a plurality of convex portions (holding portions 13a) spaced apart in the axial direction into the fixed grooves 11b of the outer member 11, the end portions of the foil 13 are formed in the fixed grooves 11b at two locations separated in the axial direction. Since it is held, the foil 13 can be held in a balanced manner in the axial direction. In the present embodiment, similarly to the embodiment shown in FIG. 7, a slit 13d is provided at the other end of the foil 13, and the holding portion 13a is inserted into the slit 13d. Not only this but illustration is omitted, but similarly to the embodiment shown in FIG. 4, a holding portion 13 b composed of a plurality of convex portions extending from the main body portion 13 c is provided at the other end of the foil 13, and this holding is performed. One holding portion 13a may be inserted into the recess between the portions 13b. Further, the attachment of the foil 13 to the outer member 11 may be performed by inserting the holding portions 13a and 13b into the fixing grooves 11b and 11c as shown in FIG. 3, or only one holding portion 13a as shown in FIG. May be inserted into the fixing groove 11b, and the other holding portion 13b may be along the inner peripheral surface 11a of the outer member 11. In FIG. 9, the convex portion constituting the holding portion 13 a is constituted by two convex portions. However, the number is not limited to this, and the number of convex portions constituting the holding portion 13 a may be three or more. In this case, the same number of slits 13d as the convex portions of the holding portion 13a are provided.

  The back foil 12 is preferably substantially the same shape as the foil 13 as described above. Therefore, for example, if the foil 13 has the shape shown in FIGS. 7 and 10, the back foil 12 preferably has substantially the same shape as these. In addition, when attaching the back foil 12 to the outer member 11 by means different from the foil 13, it is not necessary to have substantially the same shape as the foil 13.

  Further, the elastic member is not limited to the back foil 12, and any elastic member that imparts elasticity toward the inner diameter to the foil 13 can be used. For example, an elastic body in which strands are knitted in a net shape can be used.

  Although the case where three foils 13 are provided on the foil bearing 10 has been described above, the present invention is not limited thereto, and two or four or more foils 13 may be provided.

  Further, in the above description, the case where the shaft 6 is a rotation side member and the outer member 11 is a fixed side member is illustrated, but conversely, the shaft 6 is a fixed side member and the outer member 11 is rotated. Even in the case of the side member, the configuration of FIG. 3 can be applied as it is. However, in this case, since the foil 13 serves as a rotating member, it is necessary to design the foil 13 in consideration of deformation of the entire foil 13 due to centrifugal force.

  The application object of the foil bearing 10 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. 10, the turbocharger drives the turbine 51 with exhaust gas generated in the engine 53, rotates the compressor 52 with the driving force to compress the intake air, and increases the torque and efficiency of the engine 53. It is intended to improve. The rotor is constituted by the turbine 51, the compressor 52, and the shaft 6, and the foil bearing 10 of each of the above embodiments can be used as the radial bearing 10 that supports the 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. Furthermore, although the case where either one of the shaft 6 or the outer member 11 is used as a rotation-side member and the other as a fixed-side member is illustrated, both members should be used as a rotation-side member having a speed difference. You can also.

DESCRIPTION OF SYMBOLS 10 Foil bearing 11 Outer member 11b, 11c Fixing groove | channel 12 Back foil 13 Foil 13a, 13b Holding | maintenance part 13c Main-body part A Bearing surface R Radial bearing clearance

Claims (8)

  1. An outer member having a cylindrical inner peripheral surface, and a plurality of foils attached to the inner peripheral surface of the outer member, and supports a shaft inserted in the inner periphery in a radial direction so as to be relatively rotatable. A foil bearing,
    Each foil has a bearing surface and is held in a state where both ends in the circumferential direction are in contact with the outer member,
    The circumferential ends of adjacent foils are crossed in the axial direction, and the circumferential ends of the foils are arranged on the outer diameter side of the adjacent foils .
    One end of each foil in the circumferential direction is inserted into a fixing groove provided on the inner peripheral surface of the outer member, and the other end in the circumferential direction of each foil is inserted between the adjacent foil and the outer member. A foil bearing placed between the cylindrical surface of the circumference.
  2.   The foil bearing according to claim 1, wherein at least one end portion in the circumferential direction of each foil is slidable with respect to the outer member.
  3. A convex portion is formed by extending a partial region in the axial direction at one end in the circumferential direction of each foil, and is different from the convex portion at one end in the circumferential direction at the other circumferential end of each foil. The foil bearing according to claim 1 or 2 which provided the convex part which extends an axial direction field, and made the convex part of the peripheral direction edge part of an adjacent foil intersect in the direction of an axis.
  4. Each foil has a convex portion formed by extending a partial region in the axial direction at one end portion in the circumferential direction, a slit is provided at the other circumferential end portion of each foil, and the convex portion is disposed between adjacent foils. The foil bearing of Claim 1 or 2 inserted in the said slit.
  5. The foil bearing of Claim 3 or 4 with which the said convex part was provided in the several place spaced apart in the axial direction of the circumferential direction one edge part of each foil.
  6. The foil bearing according to any one of claims 1 to 5 , wherein an elastic member is provided between each foil and an inner peripheral surface of the outer member to impart elasticity toward the inner diameter of each foil.
  7. The foil bearing according to claim 6 , wherein the elastic member is a back foil.
  8. Turbo machine with a foil bearing according to any one of claims 1-7.
JP2012276907A 2012-12-19 2012-12-19 Foil bearing Active JP6104597B2 (en)

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Application Number Priority Date Filing Date Title
JP2012276907A JP6104597B2 (en) 2012-12-19 2012-12-19 Foil bearing

Applications Claiming Priority (10)

Application Number Priority Date Filing Date Title
JP2012276907A JP6104597B2 (en) 2012-12-19 2012-12-19 Foil bearing
CN201380065906.5A CN104884825B (en) 2012-12-19 2013-12-16 Thin pad bearing and turbomachinery
EP13865854.7A EP2937584B1 (en) 2012-12-19 2013-12-16 Foil bearing
US14/652,973 US9376959B2 (en) 2012-12-19 2013-12-16 Foil bearing
EP18179378.7A EP3428465A1 (en) 2012-12-19 2013-12-16 Radial foil bearing
EP18179381.1A EP3428466A1 (en) 2012-12-19 2013-12-16 Radial foil bearing
CN201710098241.8A CN107061495B (en) 2012-12-19 2013-12-16 Thin liner bearing
PCT/JP2013/083556 WO2014098005A1 (en) 2012-12-19 2013-12-16 Foil bearing
US15/158,894 US9631556B2 (en) 2012-12-19 2016-05-19 Foil bearing
US15/460,445 US9784307B2 (en) 2012-12-19 2017-03-16 Foil bearing

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JP2014119095A JP2014119095A (en) 2014-06-30
JP6104597B2 true JP6104597B2 (en) 2017-03-29

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Publication number Priority date Publication date Assignee Title
CN105765245B (en) 2013-12-12 2018-10-30 Ntn株式会社 Foil bearing and the foil bearing unit with the foil bearing and turbomachinery
JP6440999B2 (en) * 2014-08-27 2018-12-19 Ntn株式会社 Foil bearing and foil provided on the same
JP6541946B2 (en) * 2014-08-27 2019-07-10 Ntn株式会社 Foil bearing and foil provided thereto
WO2016031465A1 (en) * 2014-08-27 2016-03-03 Ntn株式会社 Foil bearing and foil disposed in same

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5935723U (en) * 1982-08-31 1984-03-06
JP2004190762A (en) * 2002-12-10 2004-07-08 Koyo Seiko Co Ltd Foil for radial foil bearing, and radial foil bearing using the same
JP2006177542A (en) * 2004-12-21 2006-07-06 Masatomo Matsuo Spring foil bearing
JP2007239962A (en) * 2006-03-10 2007-09-20 Daido Metal Co Ltd Multilobe foil gas bearing
JP2008241015A (en) * 2007-03-29 2008-10-09 Daido Metal Co Ltd Multirobe foil fluid bearing and its manufacturing method

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