JP2015113928A - Thrust foil bearing, radial foil bearing, and manufacturing methods of the bearings - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve support force of a foil bearing.SOLUTION: A foil bearing (thrust foil bearing 40) comprises a foil holder 41, and a plurality of foils 42 which are arranged while being aligned in a circumferential direction. Each foil 42 has a body part 42a having a thrust bearing face S2, and an extension part 42b extending to an outside diameter side from the body part 42a. An end part 42d of the body part 42a of each foil 42 at a rotation-direction preceding side is arranged while being overlapped on the body part 42a of the adjacent foil 42. The extension parts 42b of a plurality of the foils 42 are fixed on the same plane of the foil holder 41.

Description

  The present invention relates to a thrust foil bearing, a radial foil bearing, and a manufacturing method thereof.

  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.

  Further, since the reaction force in the thrust direction of the air flow generated by the high-speed rotation of the turbine is applied to the shaft of the gas turbine or the supercharger, it is necessary to support the shaft not only in the radial direction but also in the thrust direction. For example, Patent Documents 1 to 3 listed below show a leaf-type thrust foil bearing as a type of thrust foil bearing that supports a rotating member (thrust collar) in the thrust direction. This thrust foil bearing is provided with a plurality of leaves at a plurality of locations in the circumferential direction of the end face of the disk-shaped foil holder, and one end in the circumferential direction of each leaf is a free end, and the other in the circumferential direction of each leaf. The end is fixed to the end surface of the fixing member. When the rotating member rotates, a thrust bearing gap is formed between the bearing surface of each leaf and the end surface of the rotating member facing the leaf surface, and the rotating member is supported in a non-contact manner in the thrust direction by the fluid film of the thrust bearing gap. .

  In the above thrust foil bearing, since the leaves are spaced apart in the circumferential direction, the area between the circumferential directions of the leaves does not function as a bearing surface, and there is a possibility that the supporting force is insufficient. Further, in the above thrust foil bearing, a back foil (bump foil, spring foil) is provided below the leaf to give an elastic force to the leaf, and thereby, between the bearing surface of each leaf and the rotating member. The clearance (thrust bearing clearance) is adjusted. However, providing the back foil in this way increases the number of parts and increases the cost.

  For example, in the thrust foil bearing shown in Patent Document 4 below, the end of each leaf on the leading side in the rotational direction rides on the adjacent leaf. Thereby, while being able to provide a bearing surface in a perimeter, a back foil is abbreviate | omitted and cost can be reduced. Further, in this thrust foil bearing, the outer diameter end of each leaf is connected by a ring-shaped connecting portion, and this connecting portion is fixed to the foil holder. Therefore, other leafs are formed below the leaf forming the bearing surface. The fixing part of the foil holder is not arranged. Since the leaf is fixed to the foil holder by a fixing member, welding, or the like, the fixing portion is usually uneven. However, as described above, the fixing portion is not disposed below the bearing surface. It is possible to avoid a situation in which the unevenness of the surface adversely affects the bearing surface and prevent a decrease in the supporting force.

Japanese Utility Model Publication No. 61-36725 Japanese Utility Model Publication No. 61-38321 Japanese Unexamined Patent Publication No. 63-195212 JP 2013-61024 A

  The thrust foil bearing of Patent Document 4 is assembled in the following procedure. First, two foil members 130 and 130 ′ in which a plurality of leaves 131 and 131 ′ are connected by ring-shaped connecting portions 132 and 132 ′ are prepared {see FIG. 22 (a)}. Then, the two foil members 130 and 130 ′ are overlapped with each leaf 131 and 131 ′ riding on the adjacent leaf 131 ′ and 131 {see FIGS. 22 (b) and 22 (c)}. The two foil members 130 and 130 'thus stacked are fixed to the foil holder 120 (see FIG. 23). In this case, the leaf 131 of the lower foil member 130 is bent by riding on the leaf 131 'of the upper foil member 130'. As a result, a thrust bearing gap is formed between the bearing surface 131c of the leaf 131 and the rotating member 106, which is gradually reduced toward the leading side in the rotational direction. In addition, the leaf 131 is curved so that an elastic force is applied, and the thrust bearing clearance can be adjusted.

  On the other hand, the leaf 131 ′ of the upper foil member 130 ′ (particularly, the outer diameter portion of each leaf 131 ′) is disposed above the leaf 131 of the lower foil member 130, so The leaf 131 ′ of the foil member 130 ′ is hardly curved, and the bearing surface 131c ′ may be substantially flat in the circumferential direction. In this case, since the thrust bearing gap formed between the substantially flat bearing surface 131c ′ and the rotating member 106 is substantially constant in the circumferential direction, the fluid pressure in the thrust bearing gap is not sufficiently increased, and the supporting force is reduced. There is a risk of inviting. Further, if the leaf 131 'is not bent, sufficient elastic force is not applied to the leaf 131', so that the thrust bearing gap adjusting function does not work, and there is a possibility that the supporting force is also lowered.

  The above problems can occur not only in the thrust foil bearing but also in the radial foil bearing.

  An object of this invention is to raise the supporting force of a foil bearing.

  In order to achieve the above object, the present invention provides a thrust foil bearing comprising a foil holder and a plurality of foils attached to the foil holder and arranged in a circumferential direction, each foil having a bearing surface. A main body portion and an extending portion extending from the main body portion to the outer diameter side, and an end portion on the front side in the rotation direction of the main body portion of each foil is disposed on the main body portion of the adjacent foil. The extending portions of the plurality of foils are fixed on the same plane of the foil holder.

  In order to achieve the above object, the present invention provides a radial foil bearing comprising a foil holder and a plurality of foils attached to the inner peripheral surface of the foil holder and arranged in the circumferential direction, The foil has a main body portion having a bearing surface and an extending portion extending from the main body portion to one side in the axial direction, and the end portion of the foil main body portion in the rotation direction leading side is adjacent to the main body portion of the foil. The extending portions of the plurality of foils are fixed on the same cylindrical surface of the foil holder.

  Thus, by fixing the extending part of each foil on the same plane (or on the same cylindrical surface) of the foil holder, all the foils ride on the adjacent foils and are similarly bent. As a result, a bearing gap that gradually decreases toward the leading side in the rotational direction is formed between the bearing surface of each foil and the rotating member that is the support target. In addition, since each foil is similarly bent, a sufficient elastic force is applied to each foil, so that the adjustment function of the bearing gap can be achieved by this elastic force.

  For example, in the example shown in FIG. 14, the extending part 42b of the foil 42 extends from the main body part 42a to the outer diameter side along the radial direction, and the outer diameter part (indicated by cross-hatching) of the extending part 42b is a foil holder (holder). It is fixed to the main body 41a). In this case, due to the fluid flow accompanying the rotation of the shaft, the main body portion 42a of the foil 42 is pulled toward the rotation direction leading side (arrow direction), so that a shearing force is applied to the inner diameter portion P of the extending portion 42b, and the foil Risk of damage. On the other hand, in the example shown in FIG. 7, the extending portion 42b of the foil 42 extends from the main body portion 42a toward the outer diameter side in a direction inclined toward the rear side in the rotational direction, and the outer diameter portion of the extending portion 42b. (Indicated by cross hatching) is fixed to the foil holder 41. In this case, when the foil is pulled to the rotation direction leading side with the rotation of the shaft, the direction of the force applied to the inner diameter portion P of the extending portion 42b is mainly the tensile direction. Shear force can be reduced and foil damage can be prevented.

  The thrust foil bearing is provided, for example, on a main body portion having a bearing surface, a plurality of foils having extending portions extending from the main body portion to an outer diameter side, and an outer diameter side of the plurality of foils, A step of forming a plurality of foil members having a connecting portion for connecting the extending portions of the plurality of foils, and a plurality of the foil members are overlapped, and the end portion on the front side in the rotation direction of each main body portion is adjacent to the main body portion. A step of placing the plurality of foil members on the same plane, and a step of separating the connecting portions of the plurality of foil members from the foil. It can be manufactured in order.

  In addition, the radial foil bearing described above includes, for example, a main body portion having a bearing surface, a plurality of foils having extending portions extending from the main body portion to one axial direction, and one axial direction of the plurality of foils. A step of forming a plurality of foil members having a connecting portion that connects the extending portions of the plurality of foils, and stacking the plurality of foil members, and an end of the main body portion of each foil member on the leading side in the rotation direction A portion of the plurality of foil members overlaid on a body portion of an adjacent foil member, a step of fixing the extending portions of the plurality of foil members on the same cylindrical surface of the foil holder, It can manufacture in order through the process of isolate | separating a connection part from the said foil.

  As described above, by attaching a foil member in which a plurality of foils are connected to the foil holder to the foil holder, the assembly process is simplified and productivity is increased as compared with the case where each foil is attached to the foil holder one by one. be able to.

  In the above manufacturing method, the circumferential dimension of the boundary between the connecting portion and the extending portion of the foil member is defined as the end portion of the extending portion (the outer diameter end in the case of a thrust foil bearing, the case of a radial foil bearing). If it is made smaller than the circumferential dimension of one end part of an axial direction), a connection part and foil can be isolate | separated easily.

  As described above, according to the thrust foil bearing and the radial foil bearing of the present invention, by fixing the extending portions of the plurality of foils on the same plane or the same cylindrical surface of the foil holder, all the foils are similarly formed. Bend. Accordingly, all the foils form a bearing gap that is gradually reduced toward the leading side in the rotation direction and have a function of adjusting the bearing gap, so that the support force can be increased.

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 integrated in the said support structure. It is sectional drawing of the radial foil bearing integrated in the said foil bearing unit. (A) is a perspective view of the foil of the radial foil bearing, and (B) is a perspective view of a state in which three foils are temporarily assembled. (A) is a top view of a 1st thrust foil bearing, (B) is a top view of a 2nd thrust foil bearing. It is a top view of the foil of a 1st thrust foil bearing. It is sectional drawing of a 1st thrust foil bearing. (A) And (B) is a top view of the foil member formed by connecting several foil. It is a top view showing the state where two foil members were temporarily assembled. It is a top view which shows the state which has arrange | positioned two foil members temporarily assembled on the holder main body of a foil holder. It is a top view which shows the state which attached the fixing member to the holder main body of FIG. It is a top view of the foil concerning other embodiments. It is a top view of the foil concerning other embodiments. (A) is a plan view of two foil members used in a thrust foil bearing according to another embodiment, (B) is a plan view of the two foil members temporarily assembled, and (C) is a thrust foil bearing. It is a top view. It is sectional drawing of the thrust foil bearing of FIG.15 (C). It is a front view of the radial foil bearing which concerns on embodiment of this invention. It is a top view of the foil of the radial foil bearing of FIG. FIG. 18 is a plan development view of the radial foil bearing of FIG. 17. (A) And (B) is a top view of the foil member which connected the some foil. It is a top view of two foil members temporarily assembled. (A)-(c) is a perspective view of the foil of the conventional thrust foil bearing. FIG. 23 is a cross-sectional view of a thrust foil bearing having the foil of FIG.

  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 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 a foil bearing unit 10 that supports the rotor shaft 6 in the gas turbine. The foil bearing unit 10 includes a rotating member 20 fixed to the shaft 6, a radial foil bearing 30 that supports the shaft 6 and the rotating member 20 in the radial direction, and a first thrust that supports the shaft 6 and the rotating member 20 in the thrust direction. A foil bearing 40 and a second thrust foil bearing 50 are provided.

  As shown in FIG. 3, the rotating member 20 includes a sleeve portion 21 and a disk-like flange portion 22 that protrudes from the sleeve portion 21 to the outer diameter. The flange portion 22 is formed of, for example, a carbon fiber reinforced composite material, and the sleeve portion 21 is formed of, for example, a carbon sintered material.

  As shown in FIG. 4, the radial foil bearing 30 includes a cylindrical (cylindrical in the illustrated example) foil holder 31 and a plurality (three in the illustrated example) of foils 32 attached to the inner peripheral surface of the foil holder 31. And have. The plurality of foils 32 are arranged on the inner peripheral surface of the foil holder 31 in the circumferential direction.

  A groove 31 b is formed on the inner peripheral surface 31 a of the foil holder 31. In this embodiment, the groove | channel 31b extended along an axial direction is provided in the multiple places (three places in the example of illustration) of the foil holder 31 at equal intervals in the circumferential direction. The foil holder 31 is made of metal, and is integrally molded including the groove 31b, for example. The foil holder 31 of this embodiment is integrally molded with a sintered metal. When the foil bearing unit 10 is used in a relatively low temperature environment, the foil holder 31 may be molded with resin.

  As shown in FIG. 5A, each foil 32 includes a convex portion 32c provided at one end in the circumferential direction and a concave portion 32d provided at the other circumferential end. The convex portion 32c and the concave portion 32d of each foil 32 are provided at the same position in the axial direction. As shown in FIG. 5B, the three foils 32 can be temporarily assembled into a cylindrical shape by fitting the convex portions 32c of the foils 32 into the concave portions 32d of the adjacent foils 32. In this case, when viewed in the axial direction shown in FIG. 4, one end in the circumferential direction (convex portion 32c) of each foil 32 intersects with the other circumferential end of the adjacent foil 32 (convex portions 32e on both sides in the axial direction of the concave portion 32d). It will be in the state. In this state, both ends in the circumferential direction of each foil 32 are held by the foil holder 31. Specifically, the protrusion 32e at the other circumferential end of each foil 32 is inserted into the groove 31b of the foil holder 31, and the protrusion 32c at one circumferential end of each foil 32 is the outer diameter surface 32b of the adjacent foil 32. And the inner peripheral surface 31 a of the foil holder 31. In this case, the movement of the plurality of foils 32 in the rotational direction leading side is restricted by the protrusions 32e of the foils 32 striking the corners 31b1 of the grooves 31b. Movement is not regulated. Accordingly, the plurality of foils 32 can be moved in the circumferential direction with respect to the foil holder 31.

  The inner diameter surface 32a of each foil 32 functions as a radial bearing surface S1 (see FIG. 4). In the illustrated example, a multi-arc radial bearing surface S1 is formed by three foils 32. A member (such as a back foil) for applying elastic force to the foil 32 is not provided between the inner peripheral surface 31a of the foil holder 31 and each foil 32, and the outer diameter surface 32b of the foil 32 and the foil are not provided. The inner peripheral surface 31a of the holder 31 is slidable. The convex portion 32c of each foil 32 is disposed on the outer diameter side of the radial bearing surface S1 of the adjacent foil 32 and functions as an underfoil portion.

  The first thrust foil bearing 40 according to the embodiment of the present invention supports the flange portion 22 of the rotating member 20 from one axial side, and as shown in FIG. And a plurality of foils 42 attached to the holder 41. The foil holder 41 includes a disc-shaped holder main body 41a having a hole in the shaft center, and a fixing member 41b provided at the outer diameter end of the end surface 41a1 of the holder main body 41a. In this embodiment, the holder main body 41a of the foil holder 41 of the first thrust foil bearing 40 and the foil holder 31 of the radial foil bearing 30 are integrally formed (see FIG. 3). In the present embodiment, the fixing member 41b has an annular shape.

  As shown in FIG. 7, each foil 42 of the first thrust foil bearing 40 is integrally provided with a main body portion 42a and an extending portion 42b extending from the main body portion 42a to the outer diameter side. The edge 42e on the rear side in the rotation direction of the main body 42a extends at least at the outer diameter end in a direction inclined toward the front side in the rotation direction toward the inner diameter side. In the illustrated example, the edge 42e on the rear side in the rotation direction of the main body 42a has a substantially V shape (so-called herringbone shape) with the center portion protruding toward the preceding side in the rotation direction. In the illustrated example, the edge 42d on the rotation direction leading side of the main body 42a also has a substantially V-shape with the center portion protruding toward the rotation direction leading side. The central portions of the edges 42d and 42e of the main body 42a are rounded in an arc shape. The extending part 42b extends from the outer diameter end of the main body part 42a in a direction inclined toward the rear side in the rotation direction toward the outer diameter side. Specifically, the edges of the extending portion 42b on the rotation direction leading side and the rotation direction rear side both extend in a direction inclined toward the rotation direction rear side toward the outer diameter side.

  The extending part 42 b of each foil 42 is fixed on the same plane of the foil holder 41. In the present embodiment, each extending portion 42 b is fixed to the outer diameter end of the end surface 41 a 1 of the holder body 41 a of the foil holder 41. Specifically, the extending portions 42b are arranged on the same circumference, and the extending portions 42b are sandwiched and fixed by the holder main body 41a of the foil holder 41 and the annular fixing member 41b. In the present embodiment, the outer diameter portion (indicated by cross hatching in FIG. 7) of the extending portion 42 b of each foil 42 is fixed to the foil holder 41.

  The plurality of foils 42 are arranged at equal pitches in the circumferential direction {see FIG. 6A}. In the illustrated example, a plurality of foils 42 are overlapped with a phase shifted by half of each foil 42. The leading edge 42d in the rotational direction of each foil 42 is disposed on the adjacent foil 42 (flange portion 22 side) (see FIG. 8). That is, the rotation direction leading side portion of each foil 42 rides on the rotation direction rear side portion of the adjacent foil 42. In this embodiment, since the extending part 42b of each foil 42 is arrange | positioned on the same plane (in the example of illustration, on the end surface 41a1 of the holder main body 41a) of the foil holder 41, all the foils 42 are adjacent to the adjacent foil 42. Get on and bend in the same way. Of the main body portion 42a of each foil 42, a portion that directly faces one end surface 22a of the flange portion 22 (portion visible in FIG. 6A) functions as the thrust bearing surface S2.

  The second thrust foil bearing 50 as an embodiment of the present invention supports the flange portion 22 of the rotating member 20 from the other side in the axial direction. As shown in FIG. 6B, the foil holder 51 and the foil And a plurality of foils 52 fixed to the holder 51. The foil holder 51 includes a disc-shaped holder main body 51a having a hole in the shaft center, and a fixing member 51b provided at the outer diameter end of the end surface 51a1 of the holder main body 51a. Each foil 52 has a main body portion 52a and an extending portion 52b extending from the main body portion to the outer diameter side. Of the main body portion 52a of each foil 52, the portion that directly faces the other end surface 22b of the flange portion 22 {the portion visible in FIG. 6B} functions as the thrust bearing surface S3. In addition, since the shape and fixing method of each member of the 2nd thrust foil bearing 50 are the same as that of the 1st thrust foil bearing 40, duplication description is abbreviate | omitted.

  The foils 32, 42, 52 are formed of a metal foil having a thickness of about 20 μm to 200 μm made of a metal having a good spring property and good workability, for example, a steel material or a copper alloy. In an air dynamic pressure bearing using air as a fluid film as in this embodiment, since there is no lubricating oil in the atmosphere, it is preferable to use a stainless steel or bronze metal foil.

  The foil bearing unit 10 having the above configuration is assembled in the following procedure. First, the sleeve portion 21 of the rotating member 20 is inserted into the inner periphery of the radial foil bearing 30. Then, the 2nd thrust foil bearing 50 is attached to a 1st thrust foil bearing so that the flange part 22 of the rotating member 20 may be inserted | pinched from the axial direction both sides. Specifically, the fixing member 41b of the foil holder 41 of the first foil bearing 40 and the fixing member 51b of the foil holder 51 of the second foil bearing 50 are brought into contact with each other. 41 and 51 are fixed in the axial direction. Thus, the foil bearing unit 10 is completed.

  The shaft 6 is press-fitted into the inner periphery of the rotating member 20 of the assembled foil bearing unit 10, and part or all of the foil holders 31, 41, 51 of the foil bearings 30, 40, 50 are fixed to the housing of the gas turbine. To do. At this time, since the radial foil bearing 30, the thrust foil bearings 40 and 50, and the rotating member 20 are integrated as the foil bearing unit 10, it can be easily assembled to the gas turbine.

  When the shaft 6 rotates in one circumferential direction (the arrow direction in FIGS. 4 and 7), the radial bearing surface S1 of the foil 32 of the radial foil bearing 30 and the outer peripheral surface 21a of the sleeve portion 21 of the rotating member 20 are radially A bearing gap is formed, and the rotary member 20 and the shaft 6 are supported in the radial direction by the pressure of the air film generated in the radial bearing gap. At the same time, between the thrust bearing surface S2 of the foil 42 of the first thrust foil bearing 40 and one end surface 22a of the flange portion 22 of the rotating member 20, and the thrust bearing surface of the foil 52 of the second thrust foil bearing 50. A thrust bearing gap is formed between S3 and the other end face 22b of the flange portion 22 of the rotating member 20, and the rotating member 20 and the shaft 6 are supported in both thrust directions by the pressure of the air film generated in each thrust bearing gap. Is done.

  At this time, due to the flexibility of the foils 32, 42, 52, the bearing surfaces S 1, S 2, S 3 of the foils 32, 42, 52 depend on the operating conditions such as the load, the rotational speed of the shaft 6, and the ambient temperature. In order to deform arbitrarily, the radial bearing gap and the thrust bearing gap are automatically adjusted to appropriate widths according to the operating conditions. Therefore, even under severe conditions such as high temperature and high speed rotation, the radial bearing gap and the thrust bearing gap can be managed to the optimum width, and the rotating member 20 and the shaft 6 can be stably supported.

  Further, in the first thrust foil bearing 40 (the second thrust foil bearing 50 is also omitted hereinafter), as shown in FIG. 8, each foil 42 rides on the adjacent foil 42 to provide elasticity. The number of parts can be reduced by omitting the foil, and the cost can be reduced. Further, by fixing the extending portion 42b provided on the outer diameter side of the bearing surface S2 among the foils 42 to the foil holder 41, the fixing portion between the foil 42 and the foil holder 41 is located below the bearing surface S2. Since it is not provided, the unevenness caused by the fixed portion is not provided on the bearing surface S2. Therefore, the entire bearing surface S2 can be functioned effectively, and the supporting force is increased.

  Further, in the first thrust foil bearing 40, the extending portions 42b of the respective foils 42 are arranged on the same plane (on the end surface 41a1 of the holder main body 41a), so that all the foils 42 ride on the adjacent foils 42. Bend in the same way. Specifically, the entire radial direction of the main body portion 42a of all the foils 42 rides on the adjacent foil 42 from the end surface 41a1 of the holder main body 41a and curves. At this time, the edge 42e on the rear side in the rotation direction of the main body 42a of each foil 42 is preferably in contact with the end surface 41a1 of the holder main body 41a in the entire radial direction. As a result, a thrust bearing gap gradually reduced toward the rotation direction leading side (left side in FIG. 8) is formed between the thrust bearing surface S2 of all the foils 42 and the end surface 22a of the flange portion 22 of the rotating member 20. The Further, since each foil 42 is curved, an appropriate elastic force is applied to each foil 42. Due to the balance between the elastic force and the fluid pressure in the thrust bearing gap, the gap width of the thrust bearing gap can always be kept appropriate, and an excellent supporting force can be obtained.

  Further, the outer diameter end of the edge 42e on the rear side in the rotation direction of the main body 42a of each foil 42 extends in a direction inclined toward the front side in the rotation direction toward the inner diameter, so that the main body of the adjacent foil 42 is provided. When 42a rides on the edge 42e, a step is formed at the outer diameter end of the bearing surface S2 of the main body portion 42a that is inclined toward the inner diameter side toward the rotation direction leading side. Since the fluid (air) around the bearing surface S2 can be actively introduced into the thrust bearing gap along this step, the pressure of the fluid in the thrust bearing gap can be increased. In particular, in the present embodiment, the edge 42e on the rear side in the rotation direction of the main body portion 42a of each foil 42 is formed in a herringbone shape, so that fluid is collected at the center in the radial direction of the bearing surface S2 and fluid in the thrust bearing gap is obtained. The pressure can be further increased.

  Further, as the fluid flows due to the rotation of the shaft 6, the foils 42 of the thrust foil bearing 40 are pulled toward the rotation direction leading side. At this time, the inner diameter portion P (see FIG. 7) of the extending portion 42b of each foil 42 extends in the direction inclined toward the outer diameter side toward the rear side in the rotation direction. The direction of the applied force can be the tensile direction, not the shear direction. Thereby, damage of each foil 42 is prevented and durability of the foil 42 is improved.

  In addition, at the time of low-speed rotation immediately before the shaft 6 is stopped or immediately after starting, the bearing surface of each foil (particularly, the bearing surface of the foil 32 of the radial foil bearing 30) and the rotating member 20 slide in contact with each other. A low friction coating such as a DLC film, a titanium aluminum nitride film, a tungsten disulfide film, or a molybdenum disulfide film may be formed on both of them. Further, when the shaft 6 rotates, vibrations of the shaft 6 can be suppressed by minute sliding between the foils 32, 42, 52 and the foil holders 31, 41, 51. In order to adjust the frictional force due to this micro-sliding, the above-described low friction coating may be formed on one or both of the foils 32, 42, 52 and the foil holders 31, 41, 51. Good.

  Hereinafter, an example of the manufacturing method of the 1st thrust foil bearing 40 is shown. In addition, since the manufacturing method of the 2nd thrust foil bearing 50 is the same as that of the 1st thrust foil bearing 40, duplication description is abbreviate | omitted. Further, the foil holder 31 of the radial foil bearing 30 is integrally provided in the holder main body 41a of the foil holder 41 of the first thrust foil bearing 40, but the foil holder 31 is omitted in the following description.

  First, as shown in FIGS. 9A and 9B, two foil members 60 are formed. Although the two foil members 60 have the same shape, in FIGS. 9 to 12, one foil member 60 is shown with a dot for easy understanding. Each foil member 60 is integrally formed by pressing a single foil. Each foil member 60 includes a plurality of foils 42 and a connecting portion 61 that connects outer diameter ends thereof. In the illustrated example, the connecting portion 61 has an annular shape. Each foil member 60 is provided with half the foil 42 of the foil 42 incorporated in the first thrust foil bearing 40 at equal intervals in the circumferential direction. The circumferential dimension L1 of the boundary (the cut surface to be cut later) between the extending portion 42b and the connecting portion 61 of each foil 42 is smaller than the circumferential dimension L2 of the outer diameter end of the extending portion 42b of each foil 42. . In the present embodiment, the connecting portion 61 is provided with a plurality of protrusions 61a protruding to the inner diameter, and the circumferential dimension L1 of the boundary between the protrusion 61a and each foil 42 is the circumferential dimension of the outer diameter end of the extending portion 42b. It is smaller than L2, for example, L1 is 1/5 or less of L2.

  Next, as shown in FIG. 10, two foil members 60 are temporarily assembled. Specifically, first, two foil members 60 are stacked. Then, while the foil 42 of the upper foil member 60 and the foil 42 of the lower foil member 60 are shifted by a half pitch, the rotation direction leading side portion of the main body portion 42a of each foil 42 is replaced with the main body portion 42a of the adjacent foil 42. It is arranged so as to overlap the rear side portion in the rotation direction (front side of the paper).

  Then, as shown in FIG. 11, the two temporarily assembled foil members 60 are arranged on the end surface 41a1 of the holder body 41a. At this time, the outer diameter end of the extending portion 42b of each foil 42 is arranged along the outer diameter end of the end surface 41a1 of the holder body 41a. Moreover, the connection part 61 of the foil member 60 is distribute | arranged to the outer-diameter side rather than the holder main body 41a. In this state, each foil 42 is fixed to the foil holder 41 as shown in FIG. In the present embodiment, an annular fixing member 41b is fixed to the holder body 41a with a bolt or the like (not shown). Thereby, the outer diameter part of the extension part 42b of each foil 42 is clamped by the holder main body 41a and the fixing member 41b, and each foil 42 is fixed to the foil holder 41. Thus, the extending portions 42b of all the foils 42 are fixed on the same plane of the foil holder 41 (on the end surface 41a1 of the holder main body 41a).

  Thereafter, the connecting portion 61 of each foil member 60 is separated from the foil 42. In the present embodiment, the connecting portion 61 is separated and removed from the foil 42 by cutting the boundary between the protrusion 61 a of the connecting portion 61 and the foil 42. Thus, the first thrust foil bearing 40 shown in FIG. 6A is completed.

  The present invention is not limited to the above embodiment. Hereinafter, although other embodiment of this invention is described, the same code | symbol is attached | subjected to the location which has the same function as said embodiment, and duplication description is abbreviate | omitted.

  In the above-described embodiment, the case where the holder main body 41a of the thrust foil bearing 40 and the fixing member 41b sandwich and fix the extending portion 42b of each foil 42 has been described. You may fix to 41a or the fixing member 41b by welding, adhesion | attachment, etc. In the embodiment shown in FIG. 13, the extending part 42b of each foil 42 is fixed to the holder body 41a by welding (for example, spot welding). In this case, the region adjacent to the inner diameter side of the welding point W (the inner diameter portion P of the extending portion 42b) of the extending portion 42b extends toward the outer diameter side in a direction inclined toward the rear side in the rotational direction. . In this case as well, the direction of the force applied to the inner diameter portion P of the extending portion 42b as the shaft 6 rotates can be mainly set as the tensile direction, as in the above embodiment. Note that the foil 42 may be clamped and fixed by the holder main body 41a and the fixing member 41b, and the foil 42 may be fixed by welding or bonding to the foil holder 41. In this case, if the fixing force between the foil 42 and the foil holder 41 is sufficient by welding or adhesion, the fixing member 41b may be omitted, or the fixing member 41b may function as a simple spacer. In FIG. 13, the extending portions 42b of the foils 42 are fixed to the holder main body 41a at one welding point W. However, the present invention is not limited to this, and each extending portion 42b is fixed at two or more welding points W. You may fix to the holder main body 41a.

  In the embodiment shown in FIG. 14, the extending portion 42b of the foil 42 extends radially outward from the outer diameter end of the main body portion 42a, and the outer diameter portion of the extending portion 42b is formed of the fixing member 41b, the holder main body 41a, and the like. It is clamped and fixed by. Also in this case, since the extending part 42b is fixed on the same plane of the foil holder 41, all of the foils 42 can ride on the adjacent foils 42 and bend similarly to the above embodiment. However, since the inner diameter portion P of the extending portion 42b extends in the radial direction, when the main body portion 42a of the foil 42 is pulled toward the rotation direction leading side by the air flow accompanying the rotation of the shaft 6, the extending portion 42b. Since a force in the shearing direction mainly acts on the inner diameter portion P of the foil, the foil 42 may be damaged. Therefore, from the viewpoint of durability of the foil 42, the embodiment shown in FIG. 7 or FIG. 13 is preferable.

  In the above embodiment, the case where the first thrust foil bearing 40 is assembled using the foil member 60 in which the plurality of foils 42 of the thrust foil bearing 40 are connected by the connecting portion 61 has been described. For example, the plurality of foils 42 may be attached to the foil holder 41 one by one by welding or bonding without being connected by the connecting portion 61.

  In the thrust foil bearing 40 shown in FIG. 15, a plurality of foil members 60 and 60 ′ are fixed to the foil holder 41 including the connecting portions 61 and 61 ′. Although the two foil members 60 and 60 'have the same shape, in FIG. 16, for ease of understanding, one foil member 60' is given a dot and each foil member 60 ' The part code is indicated with “′”. The thrust foil bearing 40 is assembled in the following procedure. First, two foil members 60, 60 'are formed by connecting the outer diameter ends of the plurality of foils 42, 42' by connecting portions 61, 61 '{see FIG. 15 (A)}. Next, two foil members 60 are stacked and temporarily assembled while the rotation direction leading side end portions of the foils 42 and 42 'are stacked on the adjacent foils 42' and 42 {see FIG. 15B. }. Then, the two temporarily assembled foil members 60, 60 'are placed on the holder body 41a and fixed to the foil holder 41 using the fixing member 41b {see FIG. 15C}. As shown in FIG. 16, the fixing member 41b has an annular portion 41b1 and a pressing portion 41b2 projecting downward from the annular portion 41b1. The pressing portion 41b2 is provided, for example, on the entire circumference of the annular portion 41b1. The two overlapping connecting portions 61 and 61 'are sandwiched and fixed by the annular portion 41b1 of the fixing member 41b and the holder main body 41a. At the same time, the extending portions 42b and 42b 'of the foils 42 and 42' are sandwiched and fixed by the pressing portion 41b2 of the fixing member 41b and the holder body 41a. Accordingly, the extending portions 42b and 42b 'of all the foils 42 and 42' are fixed on the same plane of the foil holder 41 (on the end surface 41a1 of the holder main body 41a).

  Although the case where the radial foil bearing 30 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 31a of the foil holder 31, and A so-called leaf-type radial bearing foil with the other end in the circumferential direction as a free end, or a so-called bump foil-type radial bearing foil with a corrugated back foil arranged on the outer diameter of a cylindrical top foil can be used. Good.

  The shape of the foil can be changed within a range that does not substantially affect the present invention. For example, the foil of the thrust foil bearing may have a spiral shape, or the foil of the radial foil bearing may have a herringbone shape.

  In the above embodiment, the radial foil bearing 30 and the thrust foil bearings 40 and 50 are integrated as the foil bearing unit 10 and then attached to the gas turbine. However, the present invention is not limited to this. 30, 40, and 50 may be separately attached to the gas turbine.

  Moreover, in the above embodiment, although the connection part 61 of the foil member 60 is cyclic | annular, it is not restricted to this, For example, you may use the C-type connection part which has a cut in the circumferential direction one place. Alternatively, the annular connecting portion may be divided at a plurality of locations in the circumferential direction, and a plurality of foils may be provided in each divided connecting portion.

  FIG. 17 shows a radial foil bearing 70 according to an embodiment of the present invention. The radial foil bearing 70 has a tubular (cylindrical in the illustrated example) foil holder 71 and a plurality (eight in the illustrated example) of foils 72 attached to the inner peripheral surface of the foil holder 71. The plurality of foils 72 are arranged in the circumferential direction on the inner peripheral surface of the foil holder 71.

  The inner peripheral surface 71a of the foil holder 71 is a cylindrical surface. The foil holder 71 is made of metal, and is integrally molded with, for example, sintered metal.

  As shown in FIG. 18, each foil 72 has a main body portion 72a having a bearing surface and an extending portion 72b extending from the main body portion 72a to one side in the axial direction (upper side in the drawing). An edge 72c on the rear side in the rotation direction (opposite to the arrow in FIG. 18) of the main body 72a extends in a direction inclined toward the front side in the rotation direction toward the other side in the axial direction (lower side in the figure). The edge 72d on the rotation direction leading side of the main body 72a is parallel to the edge 72c on the rear side in the rotation direction.

  The extending part 72b extends in a direction inclined toward the rear side in the rotational direction from the main body part 72a toward the one side in the axial direction. As shown in FIG. 19, the end (edge 72 d) on the rotation direction leading side of the main body 72 a of each foil 72 is disposed on the main body 72 a (inner diameter side) of the adjacent foil 72. The extending portion 72 b of each foil 72 is fixed to the same cylindrical surface shape of the inner peripheral surface 71 a of the foil holder 71. In the present embodiment, the extending portion 72b is fixed to the inner peripheral surface 71a of the foil holder 71 by welding.

  The inner diameter surface of each foil 72 functions as a radial bearing surface S1 (see FIG. 17). A member (such as a back foil) for applying an elastic force to the foil 72 is not provided between the inner peripheral surface 71a of the foil holder 71 and each foil 72. The outer diameter surface of the foil 72 and the foil holder are not provided. The inner peripheral surface 71a of 71 is slidable. The rear side portion in the rotation direction of the main body portion 72a of each foil 72 is disposed on the outer diameter side of the radial bearing surface S1 of the adjacent foil 72 and functions as an underfoil portion.

  Hereinafter, an example of the manufacturing method of the radial foil bearing 70 is shown. First, as shown in FIGS. 20A and 20B, two foil members 80 are formed. The two foil members 80 have the same shape, but in FIG. 20 and FIG. 21, one foil member 80 is shown with a dot for easy understanding. Each foil member 80 is integrally formed by pressing a single foil. Each foil member 80 has a plurality of foils 72 and a strip-like connecting portion 81 that connects the outer diameter ends thereof. Each foil member 80 is provided with half (ie, four) foils 72 of the foils 72 incorporated in the radial foil bearing 70 at equal intervals in the circumferential direction. The circumferential dimension of the boundary between the extending portion 72b of each foil 72 and the connecting portion 81 (the cut surface to be cut later) is the same as that of one end (upper end in the figure) in the axial direction of the extending portion 72b of each foil 72. It is smaller than the circumferential dimension. In the present embodiment, the connecting portion 81 is provided with a plurality of protrusions 81a protruding to the inner diameter, and the protrusions 81a and the foils 72 are connected.

  Next, as shown in FIG. 21, two foil members 80 are temporarily assembled. Specifically, two foil members 80 are overlapped, and the foil 72 of the upper foil member 80 (with no dots) and the foil 72 of the lower foil member 80 (with dots) are shifted by a half pitch, The end of the main body portion 72a of the foil 72 on the front side in the rotational direction is placed on the main body portion 72a of the adjacent foil 72 (on the front side in the drawing). Thereafter, the two temporarily assembled foil members 80 are rolled and placed on the inner peripheral surface 71a of the foil holder 71 (shown by a chain line in FIG. 21). At this time, the axial end portion of the extending portion 72 b of each foil 72 is arranged along the outer diameter end of the inner peripheral surface 71 a of the foil holder 71. Further, the connecting portion 81 of the foil member 80 is disposed on the outer side in the axial direction of the foil holder 71. In this state, as shown in FIG. 19, the extending portion 72b of each foil 72 is fixed to the foil holder 71 by welding. Thus, the extending portions 72b of all the foils 72 are fixed on the same cylindrical surface (on the inner peripheral surface 71a) of the foil holder 71.

  Thereafter, the connecting portion 81 of each foil member 80 is separated from the foil 72. In the present embodiment, the connecting portion 81 is separated and removed from the foil 72 by cutting the boundary between the protrusion 81 a of the connecting portion 81 and the foil 72. Thus, the radial foil bearing 70 shown in FIG. 17 is completed.

  In the above embodiment, the connecting portions 61 and 81 are removed after the assembly of the foil bearing. However, even if the connecting portions 61 and 81 are not removed, a foil bearing can be established. However, after assembly, since the connecting portion has no function, the size of the foil bearing can be reduced by removing the connecting portion as in the above embodiment, and as a result, the turbomachine as a whole can be reduced in size and weight. Can be realized.

  The application object of the thrust foil bearing and the radial foil bearing according to the present invention is not limited to the gas turbine described above, and can be used as a bearing for supporting the rotor of the supercharger, for example. In addition, the foil bearing according to the present invention is not limited to a turbo machine such as a gas turbine or a turbocharger, and it is difficult to lubricate with a liquid such as a lubricating oil. It can be widely used as a bearing for a vehicle such as an automobile, which is used under a restriction that it is difficult to provide or resistance due to shearing of a liquid becomes a problem, and further, as a bearing 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.

6 shaft 10 foil bearing unit 20 rotating member 21 sleeve portion 22 flange portion 30 radial foil bearing 31 foil holder 32 foil 40, 50 thrust foil bearing 41, 51 foil holder 41a, 51a holder body 41b, 51b fixing member 42, 52 foil 42a , 52a Main body portions 42b, 52b Extension portion 60 Foil member 61 Connecting portion 70 Radial foil bearing 71 Foil holder 72 Foil 80 Foil member 81 Connecting portion S1 Radial bearing surface S2 Thrust bearing surface S3 Thrust bearing surface

Claims (8)

A thrust foil bearing comprising a foil holder and a plurality of foils attached to the foil holder and arranged in a circumferential direction,
Each foil has a main body portion having a bearing surface and an extending portion extending from the main body portion to the outer diameter side, and an end portion of each foil main body portion in the rotational direction leading side is adjacent to the main body portion of the foil. Placed on top of
A thrust foil bearing in which extending portions of the plurality of foils are fixed on the same plane of the foil holder.   The thrust foil bearing according to claim 1, wherein the extending portion extends in a direction inclined rearward in the rotational direction from the main body portion toward the outer diameter side. A radial foil bearing comprising a foil holder and a plurality of foils attached to the inner peripheral surface of the foil holder and arranged in the circumferential direction,
Each foil has a main body portion having a bearing surface and an extending portion extending from the main body portion to one side in the axial direction, and an end portion of the foil main body portion in the rotation direction leading side is adjacent to the main body of the foil. Placed over the part,
A radial foil bearing in which extending portions of the plurality of foils are fixed on the same cylindrical surface of the foil holder.   The radial foil bearing according to claim 3, wherein the extending portion extends in a direction inclined rearward in the rotational direction from the main body portion toward one axial side. A main body having a bearing surface, and a plurality of foils having extending portions extending from the main body to the outer diameter side, and provided on the outer diameter side of the plurality of foils, and connecting the extending portions of the plurality of foils. Forming a plurality of foil members having a connecting portion to perform,
A step of stacking the plurality of foil members, and placing the end of the main body portion of each foil member in the rotational direction leading side on the main body portion of the adjacent foil member; and
Fixing the extending portions of the plurality of foil members on the same plane of the foil holder;
A method of manufacturing a thrust foil bearing, wherein the step of separating the connecting portions of the plurality of foil members from the foil is sequentially performed.   The method for manufacturing a thrust foil bearing according to claim 5, wherein a circumferential dimension of a boundary between the connecting part and the extending part of the foil member is smaller than a circumferential dimension of an outer diameter end of the extending part. A plurality of foil members having a main body portion having a bearing surface, a plurality of foils having extending portions extending from the main body portion to one axial direction, and a connecting portion connecting the extending portions of the plurality of foils. Forming, and
A step of stacking the plurality of foil members, and placing the end of the main body portion of each foil member in the rotational direction leading side on the main body portion of the adjacent foil member; and
Fixing the extending portions of the plurality of foil members on the same cylindrical surface of the foil holder;
A method for manufacturing a radial foil bearing, wherein the step of separating the connecting portions of the plurality of foil members from the foil is sequentially performed. The manufacturing method of the radial foil bearing of Claim 7 with which the circumferential direction dimension of the boundary of the said connection part of the said foil member and the said extension part is smaller than the circumferential direction dimension of the one axial end part of the said extension part. .

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