JP2020041589A - Foil bearing - Google Patents

Abstract

To provide a foil bearing which avoids contact between engagement parts which prevent rotation of a foil and a shaft to prevent damage of the engagement parts and increase of rotational torque of the shaft.SOLUTION: A foil bearing 1 includes: a foil holder 10; and a foil member X attached to the foil holder 10. The foil member X has: a top foil part 21 having a bearing surface A; and an under foil part 23 supporting a surface of the top foil part 21 which is opposite to the bearing surface A. The under foil part 23 includes: a body part 23a; and engagement parts 23b which are provided continuing into the body part 23a in an axial direction and may engage with the foil holder 10 in a rotation direction.SELECTED DRAWING: Figure 3

Description

  The invention relates to a foil bearing.

  The foil bearing has a bearing surface formed of a thin metal plate (foil) having flexibility, and supports a load while allowing the deflection of the bearing surface. It is characterized in that the bearing gap is automatically adjusted to an appropriate width according to operating conditions such as load and ambient temperature.

  In a foil bearing, the fluid pressure in the bearing gap does not increase sufficiently during low-speed rotation immediately after the shaft stops or immediately after starting, or when the shaft is temporarily rotated in reverse. And move in the circumferential direction. For this reason, in the foil bearing, it is necessary to take measures for restricting the rotation of the foil by sliding with the shaft as described above.

  For example, if the foil is fixed to the foil holder by welding, the above problem can be prevented, but the foil may be distorted due to heat during welding. Since the bearing gap formed between the bearing surface of the foil and the outer peripheral surface of the shaft is usually a very small width of about several tens of μm, even a slight distortion of the foil adversely affects the accuracy of the bearing gap. .

  As a method of fixing a foil without using welding, for example, in Patent Document 1 below, a protrusion (ridge) is provided on an inner peripheral surface of a foil holder, and a circumferential end of the foil is provided on a side wall (stop wall) of the protrusion. The bumping restricts the circumferential movement of the foil. Further, in Patent Document 2 below, an engagement groove is provided on the inner peripheral surface of the foil holder, and a circumferential end of the foil is inserted into the engagement groove, thereby restricting the movement of the foil in the circumferential direction.

JP 2006-57828 A JP 2013-24344 A

  However, if a structure is provided in which both ends in the circumferential direction of the foil abut against the foil holder as in Patent Documents 1 and 2 described above, the design of the foil and the foil holder is limited, so that the bearing performance is sufficiently improved. May not be possible. Such a problem occurs not only in the radial foil bearing that supports the shaft in the radial direction but also in the thrust foil bearing that supports the shaft in the thrust direction.

  The present applicant has proposed a foil bearing 101 as shown in FIG. 9 in Japanese Patent Application No. 2017-139692. The foil bearing 101 includes a cylindrical foil holder 110 and three foils 120 attached to an inner peripheral surface 111 of the foil holder 110. As shown in FIG. 10, each foil 120 integrally has a top foil portion 121 having a bearing surface A and an underfoil portion 123 provided on the upstream side (the lower side in the figure) of the top foil portion 121. On the outer diameter side of the top foil portion 121 of each foil 120, an under foil portion 123 of an adjacent foil 120 is arranged. Locking portions 124 are provided on both axial sides of the top foil portion 121. As shown in FIG. 9, the locking portions 124 of the respective foils 120 are housed in concave portions 111 c formed at both axial ends of the inner peripheral surface of the foil holder 110, and the locking portions 124 and the inner walls of the concave portions 111 c are pivoted. The movement of the foil 120 to both sides in the circumferential direction with respect to the foil holder 110 is restricted by the engagement in the forward and reverse rotation directions.

  By providing the locking portions 124 that can be engaged with the foil holder 110 in the rotation direction on both sides in the axial direction of the top foil portion 121 in this way, a structure in which both circumferential ends of the foil 120 abut against the foil holder 110 is provided. Since there is no need to provide them, the degree of freedom in designing the foil 120 and the foil holder 110 is increased.

  However, when the locking portion 124 is provided on the top foil portion 121, the locking portion 124 comes close to the shaft. If the misalignment between the shaft and the foil bearing is large, the locking portion 124 comes into contact with the shaft, and There is a fear that the stop portion 124 may be damaged or the rotational torque of the shaft may be increased.

  Under the circumstances described above, the present invention further improves the foil bearing as shown in FIG. 9 so as to avoid the contact between the locking portion and the shaft, thereby damaging the locking portion and reducing the rotational torque of the shaft. The purpose is to prevent an increase.

  In order to solve the above-mentioned problem, the present invention is a foil bearing that includes a foil holder and a foil member attached to the foil holder, and supports a shaft relatively rotatably, wherein the foil member is a bearing. A top foil portion having a surface, and an under foil portion supporting a surface of the top foil portion opposite to the bearing surface, wherein the under foil portion has a main body portion and a surface along the bearing surface. Provided is a foil bearing that is provided continuously with the main body in a rotation orthogonal direction perpendicular to the relative rotation direction of the shaft and that is engaged with the foil holder in the relative rotation direction of the shaft. .

  By providing the locking portion on the underfoil portion in this manner, the locking portion can be separated from the shaft by at least the thickness of the top foil portion, as compared with the case where the locking portion is provided on the top foil portion. . Thereby, the possibility that the engaging portion and the shaft come into contact is reduced, and damage to the engaging portion and an increase in the rotational torque of the shaft can be prevented.

  In the foil bearing 101 shown in FIG. 9, the axial length of the top foil portion 121 of each foil 120 (that is, the axial length of the bearing surface A) in the axial direction of the foil holder 110 is equivalent to the provision of the locking portion 124. It is shorter than the length. On the other hand, in the foil bearing according to the present invention, since the locking portion is provided on the underfoil portion, the top foil portion can be arranged to overlap the locking portion in a direction orthogonal to the bearing surface. In this way, the top foil portion is not provided only in the region overlapping the main body portion of the under foil portion, but is extended to the region overlapping the locking portion, for example, to enlarge the bearing surface to the entire axial length of the foil holder 110. Load capacity can be increased.

  In the above-described foil bearing, it is preferable that a concave portion is provided at an end of the foil holder in a rotation orthogonal direction (axial direction for a radial bearing, radial direction for a thrust bearing), and an engaging portion is accommodated in the concave portion. Thereby, since the locking portion accommodated in the concave portion of the foil holder is arranged behind the end portion in the rotation orthogonal direction of the top foil portion, compared with the middle portion in the rotation orthogonal direction supported by the main body portion of the under foil portion. Elastic deformation easily. For this reason, even when the shaft swings and comes into contact with the rotation orthogonal direction end of the top foil portion, the damage can be reduced by easily elastically deforming the rotation orthogonal direction end of the top foil portion.

  In the above-described foil bearing, for example, the locking portion can be made engageable with the foil holder in both forward and reverse rotation directions.

  In the above-described foil bearing, if the locking portion and the foil holder can be engaged in the rotation orthogonal direction, the movement of the foil with respect to the foil holder in the rotation orthogonal direction can be restricted.

  The foil member may have, for example, a plurality of foils arranged in the direction of relative rotation of the shaft, and each foil may have the top foil portion and the under foil portion integrally. In this case, the surface opposite to the bearing surface of the top foil portion of each foil is supported by the under foil portion of the adjacent foil.

  The locking portion of the foil may be configured to include, for example, a first region that is continuous with the main body in the direction orthogonal to the rotation, and a second region that extends in the rotation direction from the first region. In this case, for example, the boundary between the first region and the second region can be plastically bent, and the second region can be hooked on a step or a groove provided in the foil holder. Alternatively, it is possible to make the boundary between the first area and the second area smoothly continuous, and to abut the tip of the second area against the inner wall or the like of the concave portion of the foil holder.

  As described above, according to the present invention, by providing the underfoil portion with the locking portion for stopping the rotation of the foil member, it is possible to avoid contact between the locking portion and the shaft, and to prevent damage to the locking portion and the shaft. Can be prevented from increasing.

It is a perspective view of the foil bearing concerning one embodiment of the present invention. It is a front view of the said foil bearing. It is the top view which expanded the foil of the above-mentioned foil bearing into the shape of a flat plate. It is a perspective view of the foil member which consists of three foils. FIG. 3 is an enlarged view of FIG. 2. It is the perspective view which expanded the foil which concerns on other embodiment. It is a side view which shows the state which folded the foil of FIG. FIG. 7 is a front view of a foil bearing having the foil of FIG. 6. It is a perspective view of the foil bearing shown by Japanese Patent Application No. 2017-139892. FIG. 10 is a plan view in which the foil of the foil bearing of FIG. 9 is developed in a flat plate shape.

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

  1 and 2 show a foil bearing 1 according to an embodiment of the present invention. The foil bearing 1 rotatably supports a shaft 2 (see FIG. 2) inserted in the inner periphery in a radial direction, and is an air dynamic pressure bearing using air as a working fluid. The foil bearing 1 has a foil holder 10 and a foil member X attached to an inner peripheral surface 11 of the foil holder 10. In the present embodiment, the foil member X is composed of a plurality of (three in the illustrated example) foils 20. In the following, in the description of each foil 20, when the shaft 2 rotates in the forward direction (the direction of the arrow in FIG. 2), the downstream side in the flow direction of the fluid with respect to the foil 20 is referred to as "downstream side", and the opposite side. Is called “upstream”. Although the three foils 20 have the same shape, FIGS. 1 and 4 show each of the foils 20 with dense hatching, sparse hatching, and no hatching for easy understanding.

  The foil holder 10 is formed in a cylindrical shape from metal, resin, or the like. As shown in FIG. 2, the inner peripheral surface 11 of the foil holder 10 is provided with a cylindrical surface 11a, an axial groove 11b, and a concave portion 11c. The cylindrical surface 11a forms most of the inner peripheral surface 11. The axial grooves 11b are provided at a plurality of positions (three positions in the illustrated example) that are circumferentially separated from each other on the inner peripheral surface 11 of the foil holder 10. In the present embodiment, both ends in the axial direction of the axial groove 11 b are open on both end surfaces in the axial direction of the foil holder 10. The concave portions 11c are provided at axial ends of the inner peripheral surface 11, and are provided at both axial ends of the inner peripheral surface 11 in the present embodiment. The concave portions 11c are provided at a plurality of positions (three positions in the illustrated example) that are separated in the circumferential direction of the inner peripheral surface 11 of the foil holder 10. The concave portion 11c in the illustrated example has a cylindrical bottom surface 11c1 and side surfaces 11c2 extending radially from both circumferential ends of the bottom surface 11c1 and connecting to the cylindrical surface 11a. The outer peripheral surface 12 of the foil holder 10 is fixed to a housing of a facility (for example, a turbo machine such as a gas turbine) in which the foil bearing 1 is incorporated.

  The foil 20 is formed of a metal having high spring properties and good workability, for example, steel or a copper alloy. The foil 20 is formed by subjecting a thin metal plate having a thickness of about 20 μm to 200 μm to press working or electric discharge working. In a pneumatic dynamic pressure bearing using air as the working fluid as in the present embodiment, since the lubricating oil does not exist in the atmosphere, the foil 20 is preferably formed of stainless steel or bronze.

  As shown in FIG. 3, the foil 20 includes a top foil portion 21 having a bearing surface A, an insertion portion 22 provided downstream of the top foil portion 21 (upper side in FIG. 3), and a top foil portion 21. An underfoil portion 23 provided on the upstream side (the lower side in FIG. 3) is integrally provided. Before being attached to the foil holder 10, the foil 20 has a flat plate shape as a whole.

  The insertion portion 22 extends downstream from the top foil portion 21. In the present embodiment, the insertion portions 22 are provided at a plurality of positions (three positions in the illustrated example) separated in the axial direction. A circumferential cut 21 a is provided near the insertion portion 22 on the downstream edge of the top foil portion 21. Note that the cut 21a may be omitted unless it is particularly necessary.

  The underfoil portion 23 includes a main body 23a and a locking portion 23b.

  The main body 23a extends upstream from the top foil 21. In the present embodiment, the notch 23a1 is provided at a plurality of locations (two locations in the illustrated example) spaced apart in the axial direction in the upstream end of the main body 23a. A slit 25 is provided at the boundary between the top foil section 21 and the under foil section 23. The slit 25 is provided at the same axial position as the insertion portion 22. The slits 25 at both ends in the axial direction extend in the axial direction and open at the axial ends of the foil 20. The slit 25 at the center in the axial direction extends in the axial direction, and a cutout extending to the upstream side is provided at the center in the axial direction.

  The locking portion 23b is provided to be continuous with the main body 23a in a direction (axial direction in the present embodiment, left and right direction in FIG. 3) orthogonal to the rotation direction of the shaft 2 in a plane along the bearing surface A. In the present embodiment, locking portions 23b are provided on both axial sides of the main body 23a. The locking portion 23b in the illustrated example includes a first region 23b1 that is continuous with the main body 23a in the axial direction, and a second region 23b2 that extends from the first region 23b1 in the circumferential direction. The first region 23b1 is continuous with the main body 23a in the axial direction. The second region 23b2 is provided on both circumferential sides of the first region 23b1. The second region 23b2 and the main body 23a are separated in the axial direction by a slit 23c.

  The above-mentioned foil 20 is assembled to the foil holder 10 in the following procedure. First, as shown in FIG. 4, by inserting the insertion portion 22 of each foil 20 into the slit 25 of the adjacent foil 20, the three foils 20 are connected to temporarily assemble the foil member X into a cylindrical shape. . Thus, when each foil 20 is rolled into a cylindrical shape, the first region 23b1 of the locking portion 23b tends to deform into a cylindrical shape following the main body portion 23a of the underfoil portion 23. On the other hand, since the second region 23b2 of the locking portion 23b is separated from the main body 23a in the axial direction, the second region 23b2 does not follow the main body 23a and has a flat plate shape extending in the tangential direction of the first region 23b1. As a result, the second region 23b2 of the locking portion 23b is disposed on the outer diameter side of the main body 23a.

  Then, the foil member X rolled into a cylindrical shape as described above is inserted into the inner periphery of the foil holder 10. Specifically, the foil member X is inserted into the inner periphery of the foil holder 10 while inserting the insertion portion 22 of each foil 20 from the axial direction into the axial groove 11b opened on the end face of the foil holder 10. At this time, as shown in FIG. 5, the main body part 23a of the under foil part 23 of each foil 20 is in contact with the top foil part 21 of the foil 20 adjacent on the upstream side and the cylindrical surface 11a of the inner peripheral surface 11 of the foil holder 10. Placed between Thus, the outer diameter surface (the surface opposite to the bearing surface A) of the top foil portion 21 of each foil 20 is supported by the main body portion 23a of the under foil portion 23 of the foil 20 adjacent on the downstream side. As described above, the foil member X including the three foils 20 is attached to the foil holder 10.

  The second region 23b2 of the locking portion 23b of the foil 20 is accommodated in concave portions 11c provided at both axial ends of the inner peripheral surface 11 of the foil holder 10. Accordingly, a space is provided on the outer diameter side of the second region 23b2 of the locking portion 23b, and the second region 23b2 is formed on the outer diameter side of the main body portion 23a, particularly, in the foil by the elastic restoring force of the locking portion 23b. The inner peripheral surface 11 of the holder 10 is disposed on the outer diameter side of the cylindrical surface 11a. At this time, the first region 23b1 and the second region 23b2 of the locking portion 23b smoothly continue, and the second region 23b2 extends substantially tangentially at the circumferential end of the first region 23b1. The tip of each second region 23b2 (the end opposite to the first region 23b1) is engaged with the concave portion 11c of the foil holder 10 in the circumferential direction (the rotation direction of the shaft 2). In the illustrated example, the tip of each second region 23b2 abuts on a corner provided at the boundary between the bottom surface 11c1 and the side surface 11c2 of the recess 11c, so that the locking portion 23b is stretched in the circumferential direction to the recess 11c. Will be accommodated.

  Thus, the circumferential movement of the foil 20 with respect to the foil holder 10 is regulated by engaging the second region 23b2 of the locking portion 23b of the foil 20 with the concave portion 11c of the foil holder 10 in the circumferential direction. In the illustrated example, the locking portion 23b of each foil 20 engages with the concave portion 11c of the foil holder 10 in any circumferential direction, thereby moving each foil 20 to both sides in the circumferential direction with respect to the foil holder 10. Is regulated. In particular, by projecting both circumferential ends of the locking portion 23b to both circumferential corners of the concave portion 11c, the movement of the foil 20 to both sides in the circumferential direction with respect to the foil holder 10 can be reliably restricted.

  In this manner, the locking portions 23b provided on both sides in the axial direction of the main body portion 23a of the underfoil portion 23 are engaged with the foil holder 10 in the circumferential direction to prevent the rotation of the foil 20. The degree of freedom in designing the foil 20 and the foil holder 10 is increased as compared with a structure in which both ends in the circumferential direction abut the foil holder 10.

  Further, by providing the locking portion 23b on the underfoil portion 23, the locking portion 23b is separated from the shaft 2 by at least the thickness of the top foil portion 21 as compared with the case where the locking portion is provided on the top foil portion 21. Can be done. Thus, the possibility that the locking portion 23b and the shaft 2 come into contact with each other is reduced, and damage to the locking portion 23b and an increase in the rotational torque of the shaft 2 can be prevented.

  Further, in the present embodiment, the second region 23b2 of the locking portion 23b of the foil 20 can be engaged with the end face of the foil holder 10 in the axial direction. In the illustrated example, the second region 23b2 of the locking portion 23b is axially engageable with an end surface 11c3 (see FIG. 2) that connects the bottom surface 11c1 of the concave portion 11c of the foil holder 10 and the cylindrical surface 11a. Thereby, axial displacement between the foil 20 and the foil holder 10 can be prevented. In particular, in the present embodiment, the locking portions 23b are provided at both ends in the axial direction of the foil 20, and the foil holder 10 is sandwiched from both sides in the axial direction by these locking portions 23b, so that the foil 20 can be moved in the axial direction with respect to the foil holder 10. Movement to both sides is regulated.

  When the shaft 2 inserted into the inner periphery of the foil bearing 1 rotates in the forward direction (the direction of the arrow in FIG. 2), the bearing surface A of the top foil portion 21 of each foil 20 of the foil bearing 1 and the outer peripheral surface of the shaft 2 2a, a bearing gap R is formed. At this time, the region on the downstream side of the top foil portion 21 of each foil 20 rides on the main body portion 23a of the under foil portion 23 of the adjacent foil 20, so that the bearing surface A of each foil 20 and the outer peripheral surface 2a of the shaft 2 A wedge-shaped bearing gap R in which the gap width gradually narrows toward the downstream side is formed between them. In the present embodiment, as shown in FIG. 5, the insertion portion 22 of each foil 20 is inserted into the axial groove 11b of the foil holder 10, so that the vicinity of the downstream end of the top foil portion 21 becomes the top foil portion. 21 is bent in a direction opposite to the bending direction of the entire 21 (the bending direction of the cylindrical surface 11a of the inner peripheral surface 11 of the foil holder 10), that is, the area 21 bulges toward the inner diameter side. Thus, a wedge-shaped bearing gap R is easily formed between the bearing surface A of each foil 20 and the outer peripheral surface 2a of the shaft 2. When air is pushed into the narrow side of the wedge-shaped bearing gap R, the pressure of the air film in the bearing gap R is increased, and the shaft 2 is supported in the radial direction by this pressure. In FIG. 2, the width of the bearing gap R is exaggerated.

  As described above, the downstream region of the top foil portion 21 rides on the under foil portion 23 of the adjacent foil, so that the top foil portion 21 is provided with a radial spring property. In the present embodiment, the top foil portion 21 is further provided with a spring property by being curved so that the vicinity of the downstream end of the top foil portion 21 is convex toward the inner diameter side. As a result, the bearing surface A of the top foil portion 21 of each foil 20 is arbitrarily deformed according to the operating conditions such as the load, the rotation speed of the shaft 2 and the ambient temperature. Automatically adjusted to width. Therefore, even under severe conditions such as high temperature and high speed rotation, the bearing gap can be controlled to the optimum width, and the shaft 2 can be stably supported.

  At this time, the area of the bearing surface A is enlarged by extending the top foil portion 21 not only to the region overlapping with the main body portion 23a of the underfoil portion 23 but also to the axial direction region overlapping with the locking portion 23b. Enhanced. In the illustrated example, a bearing surface A is formed on the entire inner peripheral surface 11 of the foil holder 10.

  Further, in the above-described foil bearing 1, the main body portion 23a of the underfoil portion 23 is disposed behind the axially intermediate portion of the top foil portion 21 (on the outer diameter side). On the other hand, behind the axial end portions of the top foil portion 21, the locking portions 23b accommodated in the concave portions 11c of the foil holder 10 are arranged. In this case, since the locking portion 23b accommodated in the concave portion 11c can escape to the outer diameter side, for example, even if the locking portion 23b swings around the shaft 2 and contacts the axial end of the top foil portion 21, the locking portion 23b The end in the axial direction of the top foil portion 21 overlapped with the top foil portion 21 is released to the outer diameter side, so that damage to the top foil portion 21 can be reduced.

  Further, since the top foil portion 21 of each foil 20 is overlapped on the inner foil side of the under foil portion 23 of the adjacent foil 20, the top foil portion 21 is moved by the fluid pressure in the bearing gap R. , A step is formed in the top foil portion 21 along the cutout portion 23a1 of the main body portion 23a of the underfoil portion 23. Fluid flowing through the bearing gap R during the rotation of the shaft 2 is collected at the axial center of each notch 23a1 along the above-described step, whereby the fluid pressure in the bearing gap R is positively increased. In the present embodiment, since the notch portions 23a1 are provided at two locations, the high-pressure portions are provided at two locations separated in the axial direction, so that the rigidity of the shaft 2 against vibration in the conical mode is increased.

  At the time of low-speed rotation immediately after the start of rotation of the shaft 2 or just before the stop, the fluid pressure in the bearing gap R is not sufficiently increased, so that the outer peripheral surface 2a of the shaft 2 and the bearing surface A of the foil 20 slide. At this time, the foil 20 attempts to move to the downstream side, but the second region 23b2 on the downstream side of the locking portion 23b of the foil 20 is engaged with the concave portion 11c of the foil holder 10 in the circumferential direction. Movement to the downstream side is regulated. In the present embodiment, the insertion portion 22 of the foil 20 abuts on the depth of the axial groove 11b of the foil holder 10, and the movement of the foil 20 on the downstream side is also regulated here. The structure for restricting the movement of the foil 20 to the downstream side may be only one of the above structures. For example, while the second region 23b2 on the downstream side of the locking portion 23b of the foil 20 is circumferentially engaged with the concave portion 11c of the foil holder 10, the downstream end of the insertion portion 22 of the foil 20 is May be arranged on the near side with respect to the depth of the axial groove 11b.

  The shaft 2 normally rotates only in the forward direction (the direction of the arrow in FIG. 2), but may rotate in the reverse direction temporarily immediately after stopping. In such a case, the outer surface 2a of the shaft 2 and the bearing surface A of the foil 20 slide, so that the foil 20 tends to move upstream. At this time, since the second region 23b2 on the upstream side of the locking portion 23b of the foil 20 is engaged with the concave portion 11c of the foil holder 10 in the circumferential direction, the movement of the foil 20 to the upstream side is restricted.

  The present invention is not limited to the above embodiment. Hereinafter, other embodiments of the present invention will be described, but the description of the same points as the above embodiments will be omitted.

  In the above embodiment, the case where the foil member X is constituted by the plurality of foils 20 has been described, but the present invention is not limited to this. For example, in the embodiment shown in FIGS. 6 to 8, the foil member X is constituted by one foil 20. As shown in FIG. 6, the foil 20 integrally has a flat top foil portion 21 and a corrugated under foil portion 23. As shown in FIG. 7, the top foil portion 21 and the under foil portion 23 are overlapped by folding back at the boundary between the top foil portion 21 and the under foil portion 23 of the foil 20. The foil bearing 1 shown in FIG. 8 is obtained by rolling this foil 20 into a cylindrical shape and inserting it into the inner periphery of the foil holder 10. The locking portions 23b provided at both ends in the axial direction of the underfoil portion 23 are accommodated in concave portions 11c provided at both ends in the axial direction on the inner peripheral surface of the foil holder 10. The top foil portion 21 is elastically supported from behind by a corrugated under foil portion 23. The second area 23b2 of the locking portion 23b is circumferentially engaged with the concave portion 11c of the foil holder 10, thereby restricting the movement of the foil 20 to both sides of the foil holder 10 in the circumferential direction.

  In the above embodiment, the case where the boundary between the first region 23b1 and the second region 23b2 of the locking portion 23b of the foil 20 is elastically bent has been described. However, the present invention is not limited to this. The foil 20 may be attached to the foil holder 10 after the boundary between the first region and the second region is plastically bent. In this case, for example, by hooking the second region of the locking portion on a step or groove provided in the foil holder, the circumferential movement of the foil 20 can be restricted.

  In the above embodiment, the locking portion 23b of the underfoil portion 23 of the foil 20 and the foil holder 10 are not completely fixed, and the circumferential end of the locking portion 23b and the inner wall of the concave portion 11c of the foil holder 10 are not fixed. The circumferential movement of the foil 20 is restricted only by the abutting structure, but the invention is not limited to this. For example, the locking portion 23b and the foil holder 10 may be completely fixed by means such as welding or bonding.

  In the above embodiment, the case where the foil bearing 1 is a radial foil bearing that supports the shaft 2 in the radial direction has been described. However, the present invention is not limited to this, and a thrust foil bearing that supports a thrust collar provided on the shaft in the thrust direction. The present invention may be applied to a device (not shown). In this case, the foil member has a top foil portion having a bearing surface, and an underfoil portion disposed between the top foil portion and the foil holder, and a locking portion is provided on the underfoil portion. The engagement of the locking portion with the disk-shaped foil holder in the circumferential direction restricts the rotation of the foil member due to sliding with the shaft.

  In the above embodiment, the case where the foil bearing 1 is fixed and the shaft 2 is rotated has been described. However, the present invention is not limited to this, and the shaft 2 may be fixed and the foil bearing 1 may be rotated. However, when the foil bearing 1 is rotated, a centrifugal force is applied to the foil. Therefore, it is necessary to design the foil so as not to be damaged by the centrifugal force.

  The foil bearing 1 described above can be used as a bearing for a vehicle such as an automobile or a bearing for an industrial device, in addition to a turbomachine such as a gas turbine or a turbocharger (supercharger).

  The foil bearing described above can be used not only as an air dynamic pressure bearing using air as a working fluid, but also as an oil dynamic pressure bearing using lubricating oil as a working fluid.

DESCRIPTION OF SYMBOLS 1 Foil bearing 2 Shaft 10 Foil holder 11c Recess 20 Foil 21 Top foil part 22 Insertion part 23 Underfoil part 23a Main body part 23b Locking part 23b1 First area 23b2 Second area X Foil member A Bearing surface R Bearing gap

Claims (9)

A foil bearing comprising a foil holder and a foil member attached to the foil holder, the shaft bearing supporting a shaft relatively rotatably,
The foil member has a top foil portion having a bearing surface, and an underfoil portion supporting a surface of the top foil portion opposite to the bearing surface,
The underfoil portion is provided continuously with the main body portion in a rotation orthogonal direction orthogonal to a relative rotation direction of the shaft in a plane along the main body portion and the bearing surface, and the foil is formed in a relative rotation direction of the shaft. A foil bearing comprising a holder and an engaging portion engageable.   The foil bearing according to claim 1, wherein the top foil portion is arranged so as to overlap with the locking portion in a direction orthogonal to the bearing surface.   3. The foil bearing according to claim 2, wherein a recess is provided at an end of the foil holder in a direction perpendicular to the rotation, and the locking portion is accommodated in the recess.   The foil bearing according to any one of claims 1 to 3, wherein the locking portion is engageable with the foil holder in both forward and reverse rotation directions.   The foil bearing according to any one of claims 1 to 4, wherein the locking portion and the foil holder can be engaged in a rotation orthogonal direction.   The said foil member has a some foil arrange | positioned in the relative rotation direction of the said axis | shaft, Each foil has the said top foil part and the said underfoil part integrally, The one in any one of Claims 1-5. Foil bearing as described.   The said locking part was provided with the 1st area | region which continued in the rotation orthogonal direction with the said main-body part, and the 2nd area | region extended in the rotation direction from the said 1st area | region is provided. Foil bearing.   The foil bearing according to claim 7, wherein a plastic bending portion is formed at a boundary between the first region and the second region of the locking portion. The foil bearing according to claim 7, wherein a boundary between the first region and the second region of the locking portion is smoothly continuous.

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