JP2015143572A - Foil, foil bearing and assembly method of foil bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance productivity of a foil bearing.SOLUTION: A foil bearing 1 includes: a foil holder 10 that has a plurality of axial grooves 14 on an inner peripheral surface 11; and a plurality of foils 20 that has a body part 21 having a bearing surface, an inserting part (a convex part 22) provided on one side in the circumferential direction of the body 21, and a fitting part (a slit 23) provided on the other side in the circumferential direction of the body part 21. The projection part 22 of each foil 20 is fitted to the slit 23 of an adjacent foil 20, and is inserted into the axial groove 14 of the foil holder 10.

Description

  The present invention relates to a foil, a foil bearing, and a method for assembling the foil bearing.

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

  For example, the following Patent Documents 1 and 2 show so-called multi-arc type foil bearings in which a plurality of foils are arranged in the circumferential direction and both ends of each foil in the circumferential direction are attached to a foil holder (housing). Yes. In these foil bearings, by striking both ends in the circumferential direction of each foil against the protruding portion (the shift suppressing portion 62 of Patent Document 1 and the peak 70 of Patent Document 2) protruding from the inner peripheral surface of the foil holder to the inner diameter, Both ends in the circumferential direction of each foil are held by the foil holder.

JP 2009-216239 A JP 2006-57828 A

  In the foil bearing as described above, since it is necessary to mount the foils one by one between the protrusions of the foil holder, man-hours are required and productivity is poor.

  The technical problem to be solved by the present invention is to increase the productivity of foil bearings.

  In order to solve the above problems, the present invention provides a foil holder having a plurality of grooves on an inner peripheral surface, a main body portion having a bearing surface, an insertion portion provided on one circumferential side of the main body portion, and A foil bearing comprising a plurality of foils having attachment portions provided on the other circumferential side of the main body, wherein the insertion portion of each foil is attached to the attachment portion of an adjacent foil, and A foil bearing inserted into a groove of a foil holder is provided.

  In order to solve the above-mentioned problems, the present invention provides a foil holder having a plurality of grooves on the inner peripheral surface, a main body having a bearing surface, an insertion portion provided on one circumferential side of the main body, And a method of assembling a foil bearing including a plurality of foils having attachment portions provided on the other circumferential side of the main body portion, wherein the insertion portion of each foil is connected to the attachment portion of the adjacent foil. A step of temporarily assembling the plurality of foils into a cylindrical shape, and a step of inserting the plurality of temporarily assembled foils into the inner periphery of the foil holder while inserting the insertion portion of each foil into the groove. And a method for assembling the foil bearing.

  Furthermore, in order to solve the above-described problem, the present invention provides a foil that is attached to an inner peripheral surface of a foil holder, the main body having a bearing surface, and provided on one side in the circumferential direction of the main body. Provided is a foil comprising an insertion part to be inserted into a groove provided on the inner peripheral surface of the holder, and an attachment part provided on the other circumferential side of the main body part to which an insertion part of an adjacent foil is attached. .

  As described above, in the foil bearing of the present invention, the insertion portion to be inserted into the groove of the foil holder is formed at one end portion in the circumferential direction of the foil, and the foil adjacent to the other end portion in the circumferential direction of the foil is formed. An attachment portion to which the insertion portion is attached is provided. Thereby, a plurality of foils can be temporarily assembled into a cylindrical shape by attaching the insertion portion of the adjacent foil to the attachment portion of each foil. The plurality of foils temporarily assembled in this manner can be attached to the foil holder at a time by inserting them into the inner periphery of the foil holder while inserting the insertion portion of each foil into the groove.

  At this time, if at least one end in the axial direction of the groove of the foil holder is opened on the end face of the foil holder, each foil is inserted from one side in the axial direction in a state where a plurality of foils are temporarily assembled in a cylindrical shape. Part can be inserted.

  In the foil bearing described above, since the plurality of foils are attached to the foil holder simply by inserting the insertion portion of each foil into the groove of the foil holder, the foil is movable with respect to the foil holder. In this case, when the shaft is inserted into and removed from the inner periphery of the foil bearing during assembly or maintenance, the foil and the shaft may slide in contact with each other in the axial direction, and the foil may shift in the axial direction with respect to the foil holder.

  Therefore, it is preferable to provide a locking member that can be engaged from one side in the axial direction at the insertion portion of the foil inserted into the groove of the foil holder. Thus, the axial movement of the foil relative to the foil holder can be restricted by engaging the foil and the locking member in the axial direction. In this case, if the locking member is to be engaged with the main body portion of the foil, the locking member needs to protrude to the inner diameter side of the inner peripheral surface of the foil holder, so that the locking member and the shaft interfere with each other. There is a fear. Therefore, as described above, when the locking member is engaged with the insertion portion of each foil inserted into the groove of the foil holder, the locking member can be accommodated in the radial direction region of the foil holder groove. Interference between the locking member and the shaft can be avoided.

  In the above foil bearing, if one end of the main body in the axial direction is extended to one side in the axial direction from one end of the insertion portion in the axial direction, the area of the bearing surface is increased, and the bearing performance is increased. Enhanced.

  For example, when the inner peripheral surface of the locking member is exposed to the inner periphery of the foil holder, the inner peripheral surface of the locking member and the outer diameter surface of the main body portion of the foil are directly opposed. At this time, if the inner peripheral surface of the locking member and the inner peripheral surface of the foil holder are arranged in the same cylindrical surface, the axial end of the main body of the foil is supported from the outer diameter side by the locking member. The In this case, when the shaft is swung around, the axial end portion of the main body portion of the foil is sandwiched between the outer peripheral surface of the shaft and the inner peripheral surface of the locking member, which may cause wear or damage to the foil. Therefore, if the inner peripheral surface of the locking member is arranged on the outer diameter side with respect to the inner peripheral surface of the foil holder, the axial end of the main body of the foil is moved to the outer diameter side by the difference in diameter between these surfaces. I can escape. Therefore, when the shaft swings, the end of the foil body in the axial direction is deflected to the outer diameter side and escaped, thereby preventing excessive interference between the shaft and the foil and suppressing wear and damage to the foil. be able to.

  Further, the inner peripheral surface of the locking member may be gradually expanded toward one side in the axial direction. In this case, it is possible to prevent excessive interference between the shaft and the foil by retracting the region including the end portion on the one axial side of the inner peripheral surface of the locking member to the outer diameter side from the inner peripheral surface of the foil holder. In addition, since the end on the other side in the axial direction of the locking member that engages with the insertion portion of the foil can be extended to the same radial position as or the vicinity of the inner peripheral surface of the foil holder, The engagement area with the stop member can be increased, and the foil can be reliably prevented from coming off.

  If the outer peripheral surface of the locking member is exposed to the outer periphery of the foil holder, the radial dimension of the locking member can be increased. Therefore, when the foil holder is thin, the locking member is processed. And attachment to the foil holder is facilitated. In addition to this, if the inner peripheral surface of the locking member is exposed to the inner periphery of the foil holder, the radial dimension of the locking member can be further increased.

  On the other hand, the inner peripheral surface of the locking member may be covered with a foil holder. In this case, since the surface directly opposite to the outer diameter surface of the foil can be entirely constituted by the inner peripheral surface of the foil holder, this surface can be processed integrally, and geometrical tolerances such as coaxiality can be obtained with high accuracy. It can be easily processed.

  By the way, in said foil bearing, each foil is attached to the foil holder in the state which can move to the circumferential direction by inserting the insertion part of each foil in the groove | channel of a foil holder. For this reason, at the time of rotation of the shaft, a minute slide occurs between each foil and the foil holder, thereby obtaining an effect of damping the vibration of the shaft. However, if each foil can move in the circumferential direction with respect to the foil holder in this way, when the shaft suddenly reversely rotates for some reason, the foil moves to the other side in the circumferential direction along with the rotation of the shaft. There is a possibility that the insertion portion of the metal will come out of the groove of the foil holder. For example, if each foil is completely fixed to the foil holder by welding or the like, such a problem can be avoided, but in this case, the vibration damping effect of the shaft due to the sliding of the foil and the foil holder as described above is greatly increased. It will decline.

  Therefore, it is preferable that the locking member is provided with a circumferential engagement portion that can be engaged with the foil from the other circumferential side. In this case, even when the shaft rotates in the reverse direction, by engaging the circumferential engagement portion of the locking member with the foil, the movement of the foil in the other circumferential direction can be restricted. It is possible to prevent a situation where the holder comes out of the groove.

  For example, the engaging member and the foil can be engaged in the circumferential direction by fitting the circumferential engaging portion of the engaging member into a recess provided in the foil. In this case, since the sliding of the foil and the foil holder is allowed if the circumferential engagement portion of the locking member and the concave portion of the foil are fitted in a state in which the movement of the foil in the circumferential direction is allowed, The vibration damping effect can be reliably obtained.

  If the circumferential direction engaging portion and the foil of the locking member are provided with axial portions parallel to the axial direction, respectively, and the axial direction portions can be engaged with each other in the circumferential direction, the movement direction of the foil relative to the foil holder (circumferential) The movement of the foil to the other side in the circumferential direction can be reliably restricted by the engagement of the axial direction portions perpendicular to the direction.

  Or it is good also as providing the inclination part which inclined with respect to the axial direction in the circumferential direction engaging part and foil of a locking member, respectively, and making both inclination parts engage in the circumferential direction. In this case, as compared with the case where the axial portions are engaged with each other as described above, the load applied to the foil can be handled in a wider region, so that the resistance of the foil to the tensile force in the circumferential direction can be increased.

  As described above, according to the present invention, the number of steps for assembling the foil bearing can be reduced and the productivity can be improved as compared with the conventional case where the foils are attached to the foil holder one by one.

It is sectional drawing (sectional drawing in the II line of FIG. 2) of the foil bearing which concerns on one Embodiment of this invention. It is sectional drawing in the II-II line of FIG. (A) is a perspective view of a foil, and (B) is a perspective view of a temporary foil assembly in which three foils are temporarily assembled. (A)-(C) are front views which show the example of a locking member (retaining ring), respectively. (A) is a fragmentary sectional perspective view which shows a mode that foil is inserted in a foil holder, (B) is a fragmentary sectional perspective view which shows a mode that the latching member was attached to the foil holder. It is sectional drawing which shows a mode that a foil temporary assembly is inserted in a foil holder. It is sectional drawing which shows a mode that a locking member is attached to a foil holder. It is an enlarged view of the C section of FIG. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment. (A) is a perspective view of a foil according to another embodiment, and (B) is a perspective view of a state in which three foils are temporarily assembled. It is a top view of the foil concerning other embodiments. It is a disassembled perspective view of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing of FIG. It is a top view of the foil integrated in the foil bearing of FIG. (A) is a fragmentary sectional perspective view which shows a mode that a foil is inserted in the foil holder of the foil bearing of FIG. 15, (B) is a fragmentary sectional perspective view which shows a mode that a locking member is attached to this foil holder. . (A) is sectional drawing which shows a mode that the axis | shaft supported by the foil bearing of FIG. 15 reversely rotated, (B) is sectional drawing which shows a mode that the said axis | shaft rotated forward. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment. It is a top view of the foil integrated in the foil bearing of FIG. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment. It is sectional drawing of the foil bearing which concerns on other embodiment.

  FIG. 1 shows a foil bearing 1 according to an embodiment of the present invention. The foil bearing 1 supports, for example, a turbine shaft 2 of a gas turbine that is a kind of turbomachine, and an outer peripheral surface thereof is fixed to an inner periphery of a housing of the gas turbine.

  The foil bearing 1 includes a foil holder 10 having a cylindrical shape (cylindrical in the illustrated example), a plurality (three in the illustrated example) of foils 20 attached to the inner peripheral surface 11 of the foil holder 10, Member 30.

  The foil holder 10 is integrally molded with a sintered metal, for example. As shown in FIG. 2, the inner peripheral surface 11 of the foil holder 10 is provided with a small-diameter inner peripheral surface 11a and a large-diameter inner peripheral surface 11b provided on one side in the axial direction of the small-diameter inner peripheral surface 11a. The material of the foil holder 10 is not limited to a sintered metal, but may be formed of other metals or resins. For example, the foil holder 10 may be a machined product of steel, a pressed product of steel plate, or an injection molded product of resin. The holder 10 can also be configured.

  A groove for attaching the foil 20 is provided on the small-diameter inner peripheral surface 11 a of the foil holder 10. In the illustrated example, a plurality of axial grooves 14 are provided on the small-diameter inner peripheral surface 11a, and more specifically, three axial grooves 14 are provided at equal intervals in the circumferential direction. One axial end of the axial groove 14 opens to an end face 16 provided on one axial side of the small-diameter inner peripheral surface 11a. As described above, since at least one end of the axial groove 14 is open to the end face, the foil holder 10 including the axial groove 14 can be integrally molded. The other axial end of the axial groove 14 does not reach the end surface 17 provided on the other axial side of the small-diameter inner peripheral surface 11a, and is closed by a locking portion 18 provided integrally with the foil holder 10. ing. Between the axial direction of the small diameter inner peripheral surface 11a and the large diameter inner peripheral surface 11b, a circumferential groove 15 to which the locking member 30 is attached is provided. In the present embodiment, the circumferential groove 15 is formed in an annular shape. The groove bottom (outer diameter portion) of the circumferential groove 15 has a larger diameter than the large diameter inner peripheral surface 11b.

  The foil 20 is formed of a metal foil having a thickness of about 20 μm to 200 μm and made of a metal having high spring properties and good workability. As a material of the metal foil, for example, a steel material or a copper alloy can be used, and specifically, stainless steel or bronze is preferably used.

  The foil 20 is attached to the inner peripheral surface 11 of the foil holder 10. In the illustrated example, three foils 20 are attached to the small-diameter inner peripheral surface 11a of the foil holder 10 in a state of being arranged in the circumferential direction. Each foil 20 is integrally formed by subjecting one metal foil to press working, etching, or wire cutting. As shown in FIG. 3A, each foil 20 includes a main body 21, a convex portion 22 provided on one circumferential side of the main body 21, and a slit provided on the other circumferential side of the main body 21. 23. In the example of illustration, the convex part 22 and the slit 23 are each provided in the multiple places (two places) spaced apart in the axial direction. The slit 23 functions as an attachment portion for attaching the convex portion 22 of the other foil 20. In the illustrated example, the convex portion 22 and the slit 23 of each foil 20 are provided at the same position in the axial direction. The axial width of the slit 23 is slightly larger than the axial width of the convex portion 22. As shown in FIG. 3B, the three foils 20 can be temporarily assembled into a cylindrical shape by inserting the convex portions 22 of the respective foils 20 into the slits 23 of the adjacent foils 20.

  As shown in FIG. 1, the convex portion 22 of each foil 20 functions as an insertion portion that is inserted into the axial groove 14 provided on the small-diameter inner peripheral surface 11 a of the foil holder 10. Of each foil 20, a region on the other side in the circumferential direction from the slit 23 functions as an underfoil portion 24 disposed behind (on the outer diameter side) of the adjacent foil 20. By the above, the circumferential direction both ends of each foil 20 are hold | maintained in the state which contacted the foil holder 10. FIG. The inner diameter surface of the main body portion 21 of each foil 20 functions as a bearing surface. In a state where the plurality of foils 20 are attached to the foil holder 10, the adjacent foils 20 intersect with each other in the circumferential direction region of the opening of the axial groove 14 as viewed in the axial direction. The ends of the 20 main body portions 21 are stretched in the circumferential direction. Thereby, each foil 20 protrudes to the outer diameter side, and a bearing surface along the small diameter inner peripheral surface 11a of the foil holder 10 is obtained.

  The locking member 30 is preferably a member that prevents the convex portions 22 of the plurality of foils 20 from being detached with a single component, for example, a retaining ring. The shape of the retaining ring is not particularly limited. For example, an annular retaining ring {see FIG. 4 (A)} continuous around the entire circumference or a retaining ring with a part of the annular ring cut {see FIG. 4 (B)}. Alternatively, a C-shaped retaining ring {see FIG. 4C) can be used. The locking member 30 is made of a metal or resin rich in elasticity. The locking member 30 is attached to the inner peripheral surface 11 of the foil holder 10. In the present embodiment, as shown in FIG. 2, the locking member 30 is mounted in the circumferential groove 15 of the foil holder 10. The outer peripheral surface of the locking member 30 has a larger diameter than the large-diameter inner peripheral surface 11 b and is approximately the same diameter as the groove bottom of the circumferential groove 15. The locking member 30 is axially engageable with the inner wall 19 on one axial side of the circumferential groove 15 and the inner wall (end surface 16) on the other axial side. The inner peripheral surface 31 of the locking member 30 is continuously arranged on the same cylindrical surface as the small-diameter inner peripheral surface 11 a of the foil holder 10. The locking member 30 may be composed of a plurality of parts divided in the circumferential direction.

  The locking member 30 is disposed at a position where it can engage with the convex portion 22 of each foil 20 in the axial direction. Specifically, as shown in FIG. 2, a locking member 30 is arranged adjacent to one side in the axial direction of a portion (a pair of convex portions 22) inserted into the axial groove 14 in each foil 20. The Thereby, the locking member 30 abuts on each foil 20 from one side in the axial direction, and movement of each foil 20 in one side in the axial direction is restricted. Specifically, as shown in FIG. 5 (A), the foil holder 10 has a convex portion 22 of each foil 20 inserted into the axial groove 14 of the foil holder 10 as shown in FIG. 5 (B). By attaching the locking member 30 to the circumferential groove 15, the locking member 30 comes into contact with the convex portion 22 of the foil 20 from one side in the axial direction. In addition, in FIG. 5, illustration of the large diameter inner peripheral surface 11b provided in the edge part of the axial direction one side of the foil holder 10 is abbreviate | omitted. Moreover, the latching | locking part 18 of the foil holder 10 is distribute | arranged adjacent to the axial direction other end side of the part (a pair of convex part 22) inserted in the axial direction groove | channel 14 among each foil 20 (refer FIG. 2). ). Thereby, the latching | locking part 18 contact | abuts to each foil 20 from the other axial side, and the movement to the other axial direction of each foil 20 is controlled. As described above, the axial position of each foil 20 with respect to the foil holder 10 is determined by engaging the locking member 30 and the locking portion 18 from both axial sides of each foil 20.

  As shown in FIG. 2, one end portion (right end in the figure) of the main body portion 21 of each foil 20 extends to one axial direction side from one end portion of the pair of convex portions 22 in the axial direction. . As a result, the inner peripheral surface 31 of the locking member 30 is covered with the main body portion 21. On the other hand, the other axial end (left end in the figure) of the body portion 21 of each foil 20 extends to the other axial end side from the other axial end of the pair of convex portions 22. Thereby, the inner peripheral surface 18 a of the locking portion 18 of the foil holder 10 is covered with the main body portion 21. In this manner, the area of the bearing surface can be increased by extending the main body portion 21 of each foil 20 to a region covering the inner diameter side of the locking member 30 and the locking portion 18. At this time, the main body portion 21 of each foil 20 directly faces the inner peripheral surface 18a of the foil holder 10 and the inner peripheral surface 31 of the locking member 30 in the radial direction. In addition, you may extend the axial direction edge part of the foil 20 to the axial direction outer side beyond the locking member 30 and the locking part 18. FIG.

  The foil bearing 1 having the above configuration is assembled in the following procedure.

  First, by inserting the convex portions 22 of the foils 20 into the slits 23 of the adjacent foils 20, the three foils 20 are temporarily assembled into a cylindrical shape to form the foil temporary assembly X {see FIG. 3 (B). }.

  Next, as shown in FIG. 6, while inserting the convex portion 22 of each foil 20 of the temporary foil assembly X into the axial groove 14 of the foil holder from one axial side (the opening side of the axial groove 14), The foil temporary assembly X is inserted into the inner periphery of the foil holder 10. And the convex part 22 of each foil 20 is contact | abutted to the edge part (engagement part 18) of the axial direction groove | channel 14, and insertion to the foil holder 10 of the foil temporary assembly X is completed.

  Thereafter, as shown in FIG. 7, the locking member 30 is attached to the circumferential groove 15 of the foil holder 10. More specifically, the locking member 30 is inserted from one side in the axial direction of the foil holder 10 while being elastically deformed, and is passed through the inner periphery of the large-diameter inner peripheral surface 11b. When the locking member 30 reaches the circumferential groove 15, the locking member 30 is elastically restored and fitted into the circumferential groove 15. Thus, the foil bearing 1 is completed.

  As described above, by providing the insertion portions (protrusions 22) and the attachment portions (slits 23) in each foil 20, a plurality of foils 20 can be temporarily assembled before being attached to the foil holder 10. Thereby, compared with the case where each foil 20 is attached to the foil holder 10 one by one, assembly is facilitated and productivity is enhanced. In particular, the projection 22 of the temporarily assembled foil 20 is inserted into the axial groove 14 from the opening side in the axial direction by opening one axial end of the axial groove 14 of the foil holder 10 in the end face 16. As a result, assembly is further facilitated.

  The above-described foil bearing 1 has a shaft 2 inserted on the inner periphery thereof and is incorporated in a gas turbine. Further, during the maintenance of the gas turbine, the shaft 2 is pulled out from the inner periphery of the foil bearing 1, and after inspection and parts replacement, the shaft 2 is inserted into the inner periphery of the foil bearing 1 again. As described above, when the shaft 2 is inserted into and removed from the inner periphery of the foil bearing 1, the axial force is applied to the foil 20 by sliding the shaft 2 and the foil 20. In the foil bearing 1 described above, the foil 20 is not completely fixed to the foil holder 10 by welding or adhesion, and movement relative to the foil holder 10 is allowed. Therefore, there is a concern that the foil 20 may be displaced with respect to the foil holder 10 in the axial direction due to sliding of the shaft 2 when the shaft 2 is inserted into and removed from the inner periphery of the foil bearing 1. In this regard, in the present embodiment, as described above, the insertion portion (a pair of convex portions 22) of each foil 20 is locked from both sides in the axial direction by the locking member 30 and the locking portion 18, The axial movement of each foil 20 with respect to the foil holder 10 is restricted. Thereby, the situation where the foil 20 shifts in the axial direction with respect to the foil holder 10 due to the sliding of the shaft 2 when the shaft 2 is inserted into and removed from the inner periphery of the foil bearing 1 can be prevented.

  When the shaft 2 inserted in the inner periphery of the foil bearing 1 rotates in one circumferential direction (the arrow direction in FIG. 1), a radial bearing gap is formed between the bearing surface of the foil 20 of the foil bearing 1 and the outer peripheral surface 2a of the shaft 2. The shaft 2 is supported in the radial direction by the pressure of the air film generated in the radial bearing gap. At this time, due to the flexibility of the foil 20, the bearing surface of each foil 20 is arbitrarily deformed according to the operating conditions such as the load, the rotational speed of the shaft 2, the ambient temperature, etc. It is automatically adjusted to the appropriate width. Therefore, the radial bearing gap can be managed to the optimum width even under severe conditions such as high temperature and high speed rotation, and the shaft 2 can be stably supported.

  Specifically, as the pressure of the air pressure in the radial bearing gap increases as the shaft 2 rotates, each foil 20 is pushed into the outer diameter side. At this time, a portion of the main body portion 21 of each foil 20 that rides on the underfoil portion 24 of the adjacent foil is curved. Furthermore, in this embodiment, each foil 20 is pushed into the rotation direction leading side by the friction with the shaft 2 and the viscosity of the air, and as shown in FIG. 8, the main body portion 21 (bearing surface) of each foil 20 has an inner diameter. Curved to be convex to the side. The shape of the foil 20 is maintained at a position where the elastic force of the curved portion of the foil 20 and the pressure of the air film formed in the radial bearing gap are balanced. In the illustrated example, the convex portion 22 of each foil 20 is curved so as to be convex toward the outer diameter side inside the axial groove 14.

  During the operation of the bearing, the foil 20 is pressed against the foil holder 10 due to the influence of the air film formed in the radial bearing gap, and accordingly, a slight sliding occurs between the two. The vibration of the shaft 2 can be attenuated by the frictional energy generated by the minute sliding. In the present embodiment, the foils 20 are attached to the foil holder 10 simply by inserting the convex portions 22 of the foils 20 into the axial grooves 14. For this reason, each foil 20 is not completely fixed to the foil holder 10, and movement with respect to the foil holder 10 is allowed. In this case, when the shaft 2 rotates, the foil 20 moves in the circumferential direction with respect to the foil holder 10, so that the sliding amount of both increases, and the effect of damping the vibration of the shaft 2 is further enhanced. In the illustrated example, an end portion (underfoil portion 24) on the rear side in the rotation direction of each foil 20 is disposed between the adjacent foil 20 and the small-diameter inner peripheral surface 11 a of the foil holder 10. Since 24 slides in the circumferential direction in a state of surface contact with the small-diameter inner peripheral surface 11a of the foil holder 10, the vibration damping effect of the shaft 2 is further enhanced.

  Note that the bearing surface of each foil 20 and the outer peripheral surface of the shaft 2 are in sliding contact with each other at the time of low-speed rotation immediately before the shaft 2 is stopped or immediately after starting. A low friction coating such as a ride film, a tungsten disulfide film, or a molybdenum disulfide film may be formed. Moreover, in order to adjust the frictional force between the foil 20 and the foil holder 10 during the operation of the bearing, the above-described low friction coating may be formed on one or both of them.

  The present invention is not limited to the above embodiment. For example, in the embodiment shown in FIG. 9, the inner peripheral surface 31 of the locking member 30 is arranged on the outer diameter side with respect to the small-diameter inner peripheral surface 11 a of the foil holder 10. As a result, even if the shaft 2 swings (conical), the foil can bend to the outer diameter side, so that excessive interference between the shaft 2 and the foil 20 can be prevented, and the foil can be worn or damaged. Can be suppressed.

  In the embodiment shown in FIGS. 10 and 11, the inner peripheral surface 31 of the locking member 30 gradually increases in diameter toward one side in the axial direction (right side in the drawing). Specifically, in FIG. 10, the inner peripheral surface 31 of the locking member 30 is a conical surface. On the other hand, in FIG. 11, the inner peripheral surface 31 of the locking member 30 has a circular arc shape that protrudes toward the inner diameter side. As a result, the end surface 32 on the other axial side (left side in the figure) of the locking member 30 is extended to the inner diameter side as compared with the embodiment of FIG. It can be placed in the vicinity. For this reason, the contact area | region of the latching member 30 and the convex part 22 of the foil 20 increases, and the foil 20 can be reliably prevented from coming off. In particular, in the embodiment shown in FIG. 11, since the inner peripheral surface 31 of the locking member 30 is smoothly continuous with the small-diameter inner peripheral surface 11a of the foil holder 10, no edge is formed at these boundary portions, and the shaft The shaft 2, the foil 20, and the foil holder 10 can be reliably prevented from being damaged due to the swinging motion of 2.

  The embodiment shown in FIG. 12 differs from the above embodiment in that the circumferential groove 15 of the foil holder 10 and the large-diameter inner peripheral surface 11b have the same diameter. In the present embodiment, the locking member 30 is fitted into the circumferential groove 15 of the foil holder 10, and the end surface 32 on the other axial side (left side in the drawing) of the locking member 30 is the end surface 16 (shoulder) of the foil holder 10. Surface). The locking member 30 is fixed to the foil holder 10 by appropriate means such as press-fitting, adhesion, and screwing. Alternatively, after the locking member 30 is disposed at the illustrated position, the locking member 30 is fixed to the foil holder 10 by plastically deforming (clamping) the large-diameter inner peripheral surface 11b of the foil holder 10 toward the inner diameter side. May be. According to this embodiment, since it is not necessary to elastically deform the locking member 30 at the time of attachment to the foil holder 10, the range of selection of the material of the locking member 30 is widened, and for example, a molten material such as stainless steel is used. You can also In the present embodiment, the large-diameter inner peripheral surface 11b of the foil holder 10 may be omitted, and the end surface on the axially outer side of the locking member 30 and the end surface of the foil holder 10 may be flush with each other.

  In the above embodiment, the case where the foil 20 is provided with the slit 23 as the attachment portion has been described, but the present invention is not limited thereto. For example, as shown in FIG. 13 (A), a recess 25 as an attachment portion may be provided at the other circumferential end of each foil 20. In this case, as shown in FIG. 13B, the plurality of foils 20 can be temporarily assembled by inserting the convex portions 22 of the respective foils 20 into the concave portions 25 of the adjacent foils 20.

  Or as shown in FIG. 14, you may open the slit 23 provided in the foil 20 in an axial direction edge part. At this time, each convex portion 22 of the foil 20 extends to the axial end portion. In addition, a minute slit 28 is provided in the vicinity of the boundary between the main body portion 21 and the convex portion 22 (particularly near the corner portion formed by the main body portion 21 and the convex portion 22), and thereby the bending of the foil 20. Sometimes preventing local swells from occurring. In the illustrated example, a minute slit 28 extending in the axial direction is formed on the inner side in the axial direction of the corner portion formed by the main body portion 21 and the convex portion 22.

  In the above embodiment, the structure in which the locking member 30 is provided only at one axial end of the foil holder 10 is shown. However, the present invention is not limited thereto, and the locking member 30 may be provided at both axial ends of the foil holder 10. In this case, since the axial groove 14 can be formed in the entire axial length of the inner peripheral surface 11 of the foil holder 10, the machining of the axial groove 14 becomes easier.

  The embodiment shown in FIG. 15 differs from the above-described embodiment in that the locking member 30 is provided with an axial protrusion 33. The axial projection 33 functions as a circumferential engagement portion that can engage with the foil 20 in the circumferential direction. The axial projection 33 is provided in the radial region of the axial groove 14 of the foil holder 10. In the present embodiment, an axial protrusion 33 is provided at the inner diameter end of the locking member 30. In the present embodiment, the axial groove 14 of the foil holder 10 opens on both axial sides, and the circumferential grooves 15 are provided at both axial ends of the foil holder 10, and the locking member 30 is provided in each circumferential groove 15. Is attached. As shown in FIG. 16, the inner peripheral surface 31 of the locking member 30 is exposed to the inner periphery of the foil holder 10. In the illustrated example, the inner peripheral surface 31 of the locking member 30 and the small-diameter inner peripheral surface 11a of the foil holder 10 are continuous on the same cylindrical surface. In FIG. 16, the foil 20 is not shown.

  As shown in FIG. 17, the foil 20 used in this embodiment has recesses 26 formed at the edges on both sides in the axial direction. In the example of illustration, the rectangular recessed part 26 is provided in the edge of the axial direction outer side of each convex part 22, respectively. The concave portion 26 is provided in a region on the other axial side (right side in the drawing) of each convex portion 22. When the convex portion 22 of the foil 20 is inserted into the axial groove 14 of the foil holder 10 (see FIG. 18A) and the locking member 30 is attached to the foil holder 10, the locking member 30 is inserted into the concave portion 26 of each foil 20. The axial protrusions 33 of these are fitted {see FIG. 18B}.

  As shown by a dotted arrow in FIG. 19A, when the shaft 2 rotates in reverse for some reason and the foil 20 tries to move in the reverse direction (the other side in the circumferential direction), the outer peripheral surface 33a of the axial projection 33 is The foil 20 is engaged from the other circumferential side. Specifically, a corner portion P formed by the outer peripheral surface 33a of the axial protrusion 33 and the inner wall of the axial groove 14 of the foil holder 10 is on the other edge in the circumferential direction on the one edge 26a in the circumferential direction of the concave portion 26 of the foil 20. Engage from. Thereby, the movement to the other circumferential side of the foil 20 is restricted, and the situation where the convex portion 22 of the foil 20 comes off from the axial groove 14 of the foil holder 10 can be prevented. At this time, since the outer peripheral surface 33a of the axial projection 33 and the edge 26a on one circumferential side of the concave portion 26 of the foil 20 are both parallel to the axial direction (see FIGS. 16 and 17), the circumference of the foil 20 is The movement in the direction can be reliably regulated by the engagement of the portions (axial portions) in the direction orthogonal to the moving direction.

  In addition, when the shaft 2 is rotated in the forward direction as indicated by a solid arrow in FIG. 19B, the foil 20 moves to one side in the circumferential direction, and the tip of the convex portion 22 of each foil 20 is in the axial groove 14. It hits the inner wall. In this state, the movement of each foil 20 to the other circumferential side is not restricted by the axial protrusion 33. As a result, the minute movement in the circumferential direction of each foil 20 is not hindered by the axial projection 33 of the locking member 30, so that the vibration damping effect of the shaft 2 due to sliding between each foil 20 and the foil holder 10 is achieved. Is fully demonstrated.

  In the embodiment shown in FIG. 20, the inner peripheral surface 31 of the locking member 30 is covered with the foil holder 10. Thereby, since the surface (small-diameter inner peripheral surface 11a) directly facing the main body portion 21 of the foil 20 in the radial direction can be integrally processed, geometrical tolerance such as coaxiality can be easily processed with high accuracy. it can. In this case, the radial dimension of the locking member 30 is reduced, but in this embodiment, the outer circumferential surface 34 of the locking member 30 is exposed to the outer periphery of the foil holder 10, so that the radial direction of the locking member 30 is obtained. The dimensions are secured. Thereby, the process of the locking member 30 and the attachment to the foil holder 10 are facilitated.

  In the embodiment shown in FIG. 21, the inner peripheral surface 31 of the locking member 30 is exposed to the inner periphery of the foil holder 10, and the outer peripheral surface 34 of the locking member 30 is exposed to the outer periphery of the foil holder 10. Thereby, the radial direction dimension of the locking member 30 can further be expanded rather than the embodiment of FIG. In the present embodiment, the axial protrusion 33 is provided at the radial intermediate portion of the locking member 30.

  In the embodiment shown in FIG. 22, the locking member 30 is configured only by a portion corresponding to the axial projection 33, and both the inner peripheral surface 31 and the outer peripheral surface 34 are covered with the foil holder 10. In this case, the size of the locking member 30 in the radial direction can be suppressed and the size can be reduced.

  In the embodiment shown in FIGS. 23 and 24, an inclined portion that is inclined with respect to the axial direction is provided in a portion of the locking member 30 and the foil 20 that are engaged with each other in the circumferential direction. In FIG. 23, an inclined surface 35 as an inclined portion is provided on the outer peripheral surface of the locking member 30, and the inclined surface 35 functions as a circumferential engagement portion that can be engaged with the foil 20 from the other circumferential side. For example, the inclined surface 35 is formed in a tapered surface shape that is inclined inward in the axial direction toward the inner diameter side. In the foil 20 of FIG. 24, an inclined portion 27 is provided on the outer edge of the convex portion 22 in the axial direction. For example, the inclined portion 27 is formed in a linear shape that is inclined outward in the axial direction toward one side in the circumferential direction (left side in the figure). When the foil bearing 1 of the present embodiment is assembled, the convex portion formed by the inclined surface 35 of the locking member 30 is fitted into the concave portion formed by the inclined portion 27 of the foil 20. In this case, when the shaft 2 rotates in the reverse direction and the foil 20 tries to move to the other circumferential side, the inclined surface 35 of the locking member 30 engages with the inclined portion 27 of the foil 20 from the other circumferential side. Thus, the circumferential movement of the foil 20 is restricted.

  By the way, as in the embodiment shown in FIG. 17, when the locking member 30 and the foil 20 are engaged with each other in a portion (axial portion) parallel to the axial direction, a load is applied to the edge 26 a of the concave portion 26 of the foil 20. Therefore, a region on the one side in the axial direction from the edge 26a (region indicated by X in FIG. 17) of the convex portion 22 receives a shearing force. On the other hand, in the embodiment shown in FIG. 24, a load is applied to the inclined portion 27 of the foil 20 due to the engagement with the inclined surface 35 of the locking member 30, so almost the entire area of the convex portion 22 (Y in FIG. 24). (Shown area) receives shear force. In this case, as compared with the embodiment shown in FIG. 17, the region that receives the shearing force is widened, and thus the resistance to the tensile force in the circumferential direction is increased.

  In the embodiment shown in FIG. 25, the inner peripheral surface 31 of the locking member 30 is covered with the foil holder 10, and the cylindrical outer peripheral surface 34 of the locking member 30 is exposed to the outer periphery of the foil holder 10. This is different from the embodiment shown in FIG. In the embodiment shown in FIG. 26, the inner peripheral surface 31 of the locking member 30 is exposed to the inner periphery of the foil holder 10, and the outer peripheral surface 34 of the locking member 30 is exposed to the outer periphery of the foil holder 10. This is different from the embodiment shown in FIG. The embodiment shown in FIG. 27 is different from the embodiment shown in FIG. 23 in that both the inner peripheral surface and the outer peripheral surface of the locking member 30 are covered with the foil holder 10.

  In the above embodiment, the case where the locking member 30 is provided on the foil bearing 1 in which the temporary assemblies X of the plurality of foils 20 are attached to the foil holder 10 has been described. In the case of a foil bearing that is mounted so as to be movable in the direction, it is effective to provide the locking member 30. That is, in a foil bearing provided with a foil holder having a plurality of grooves on the inner peripheral surface and a plurality of foils having a bearing surface, each foil being attached to the foil holder in an axially movable state, It is effective to provide a locking member that can be engaged with the foil in the axial direction.

  The foil bearing according to the present invention is not limited to a turbomachine such as a gas turbine or a supercharger, but can be widely used as a bearing for a vehicle such as an automobile, 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.

DESCRIPTION OF SYMBOLS 1 Foil bearing 2 Shaft 10 Foil holder 11 Inner peripheral surface 12 Outer peripheral surface 14 Axis direction groove | channel 15 Circumferential direction groove | channel 20 Foil 21 Main-body part 22 Convex part (insertion part)
23 Slit (Mounting part)
24 Underfoil part 30 Locking member 33 Axial protrusion (circumferential engagement part)
X Foil temporary assembly

Claims (18)

A foil holder having a plurality of grooves on the inner peripheral surface, a main body portion having a bearing surface, an insertion portion provided on one circumferential side of the main body portion, and provided on the other circumferential side of the main body portion. A foil bearing comprising a plurality of foils having mounting portions,
A foil bearing in which the insertion portion of each foil is attached to the attachment portion of an adjacent foil and is inserted into a groove of the foil holder.   2. The foil bearing according to claim 1, wherein at least one end portion in the axial direction of the groove of the foil holder is open to an end surface of the foil holder.   The foil bearing of Claim 1 or 2 further provided with the latching member which can be engaged from the axial direction one side to the insertion part of the said foil inserted in the groove | channel of the said foil holder.   4. The foil bearing according to claim 3, wherein in each of the foils, one end portion in the axial direction of the main body portion extends to one side in the axial direction from one end portion in the axial direction of the insertion portion.   The foil bearing according to claim 4, wherein an inner peripheral surface of the locking member is exposed on an inner periphery of the foil holder.   The foil bearing according to claim 5, wherein an inner peripheral surface of the locking member is disposed on an outer diameter side with respect to an inner peripheral surface of the foil holder.   The foil bearing according to claim 5 or 6, wherein the inner peripheral surface of the locking member is gradually expanded in diameter toward one side in the axial direction.   The foil bearing according to any one of claims 3 to 7, wherein an outer peripheral surface of the locking member is exposed on an outer periphery of the foil holder.   The foil bearing according to claim 3 or 4, wherein an inner peripheral surface of the locking member is covered with the foil holder.   The foil bearing in any one of Claims 3-9 which provided the circumferential direction engaging part which can be engaged with the said locking member from the circumferential direction other side to the said foil.   The foil bearing according to claim 10, wherein the engagement member and the foil can be engaged in the circumferential direction by fitting a circumferential engagement portion of the engagement member into a recess provided in the foil.   The foil bearing according to claim 11, wherein the circumferential engagement portion of the locking member and the concave portion of the foil are fitted in a state in which the circumferential movement of the foil is allowed.   The circumferential engagement portion and the foil of the locking member are each provided with an axial portion parallel to the axial direction, and both axial portions can be engaged in the circumferential direction. The foil bearing described.   The circumferentially engaging portion and the foil of the locking member are provided with inclined portions inclined with respect to the axial direction, respectively, and both inclined portions can be engaged with each other in the circumferential direction. The foil bearing described. A foil holder having a plurality of grooves on the inner peripheral surface, a main body portion having a bearing surface, an insertion portion provided on one circumferential side of the main body portion, and provided on the other circumferential side of the main body portion. A method of assembling a foil bearing comprising a plurality of foils having mounting portions,
Attaching the insertion part of each foil to the attachment part of the adjacent foil, and temporarily assembling the plurality of foils into a tubular shape;
And inserting the plurality of temporarily assembled foils into an inner periphery of the foil holder while inserting insertion portions of the foils into the grooves.   16. The method of assembling a foil bearing according to claim 15, wherein at least one end portion in the axial direction of the groove opens to an end face of the foil holder, and an insertion portion of each foil is inserted into the groove from one axial side.   The foil according to claim 16, wherein after the plurality of foils are inserted into the inner periphery of the foil holder, a locking member that can be engaged with the insertion portion of the plurality of foils from one side in the axial direction is attached to the foil holder. Bearing assembly method. A foil attached to the inner peripheral surface of the foil holder,
A main body having a bearing surface, a plug provided on one side in the circumferential direction of the main body and inserted into a groove provided on an inner peripheral surface of the foil holder, and provided on the other circumferential side of the main body And a mounting portion to which an insertion portion of the adjacent foil is attached.

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