Journal foil air bearing prevents bump foil separation.

Abstract

The present invention relates to a journal foil air bearing for supporting a load applied in the radial direction of a rotating shaft rotating around a center line, the journal foil air bearing including: a top foil arranged to face the outer circumferential surface of the rotating shaft and arranged to surround the rotating shaft; a bump foil that is an elastically deformable member arranged to surround the top foil; a base foil that is a circular pipe member arranged to surround the bump foil and extends a predetermined length along the center line, and has a hollow formed therein with the center line as the center of the circle; and at least one separation prevention part provided on the base foil, which restrains the bump foil accommodated in the hollow of the base foil from separating along the longitudinal direction of the rotating shaft; the separation prevention part protrudes a predetermined length toward the rotating shaft and is provided so that an end part does not come into contact with the surface of the rotating shaft. According to the present invention, the first top foil is not pushed out in the longitudinal direction of the rotating shaft during operation, so that the performance of the bearing is not reduced, and the pushed out first top foil does not come into contact with other parts, causing serious secondary damage.

Description

Technical Field

[0001] The present invention relates to a journal foil air bearing, and more particularly to a journal foil air bearing in which a bump foil is not pushed out in the longitudinal direction of a rotating shaft during operation, and performance degradation and damage of the bearing do not occur.

Background Art

[0002] An air bearing is a bearing that lifts a rotating shaft with the pressure of compressed air between the rotating shaft and the bearing to support a load.

[0003] Such an air bearing moves together with a surface on which a gas having viscosity like air moves. When the gas meets a stop surface and is compressed, the pressure of the air confined between the moving surface and the stop surface rises to lift the moving surface. The principle is utilized.

[0004] Air bearings include a thrust air bearing for supporting a load applied along the longitudinal direction of a rotating shaft and a journal air bearing for supporting a load applied along the radial direction of a rotating shaft.

[0005] There is a journal foil air bearing which is a type of journal air bearing and uses a thin material foil to more advantageously form pressure and enhance dynamic stability at high speeds.

[0006] FIG. 17 shows an example of such a journal foil air bearing 1. The journal foil air bearing 1 is arranged to face the outer peripheral surface of a rotating shaft F that rotates in a predetermined rotation direction W, and includes a top foil 2 that surrounds the rotating shaft F and a bump foil 3 that is arranged to surround the top foil 2 as an elastically deformable wave-shaped member. One end portions of the top foil 2 and the bump foil 3 are welded to a welded portion 4 on the inner surface of a bearing housing S.

[0007] However, the conventional journal foil air bearing 1 has a relatively reduced number of parts, which is advantageous in terms of dimensional control of the bearing housing S. However, there are problems in that the work of mounting or dismounting the bearing in the bearing housing S is very inconvenient, and it is very difficult to store and manage the bearing parts 2 and 3 at the work site.

[0008] In addition, in the conventional journal foil air bearing 1, the bump foil 3 is directly attached to the inner surface of the bearing housing S, so the inner surface of the bearing housing S must be processed to have a certain roughness in addition to the shape and dimensions. Therefore, special processes such as grinding and coating must be additionally performed on the inner surface of the bearing housing S, which increases the overall product cost.

[0009] Meanwhile, in a conventional journal foil air bearing 1, the top foil 2 and bump foil 3 are fixed to the inner surface of the bearing housing S by welding. A wide variety of methods have been used other than welding, such as fixing using a key or fixing using a bolt and pin. However, such methods have problems such as technical uncertainty, difficulty in assembly / disassembly, and increased product costs.

[0010] In order to solve the above-mentioned problems, the Korean Patent Registration Publication (Registration No. 10-1558490, Registration Date: October 1, 2015) discloses a journal foil air bearing in which a base foil, a bump foil, and a top foil are first modularized into a single block by bonding them together using a bonding means, and then the blocks are attached.

[0011] However, the conventional journal foil air bearing 1 and the journal foil air bearing of the Korean Patent Registration No. 10-1558490 have a problem in that the unfixed end (free end) of the top foil or bump foil is pushed out in the direction of the rotation axis during operation due to frequent start / stop, external vibration and impact, etc. In such a case, not only does the performance of the bearing deteriorate, but the pushed-out bump foil and top foil come into contact with other parts and are worn away, resulting in serious secondary damage.

[0012] In order to solve this problem, after assembling the bearing, a circular anti-detachment ring is attached to the side of the bearing to prevent the unfixed end (free end) of the top foil or bump foil from being pushed out in the direction of the rotation axis. However, this method has the problem of increasing the overall assembly time.

[0013] In addition, when using a conventional anti-detachment ring, there is a problem that a sufficient distance must be secured between the inner peripheral surface of the anti-detachment ring and the rotating shaft in order to prevent physical contact between the inner peripheral surface of the anti-detachment ring and the rotating shaft. Although this problem can ensure to some extent the effect of preventing the bump foil from detaching, there is also a problem that it is not possible to prevent the top foil, which is arranged very close to the surface of the rotating shaft, from detaching. Summary of the Invention [Problem to be solved by the invention]

[0014] The present invention has been devised to solve the above problems, and its purpose is to provide a journal foil air bearing with an improved structure so that the bump foil is not pushed out in the longitudinal direction of the rotating shaft during operation, thereby preventing performance degradation and damage to the bearing. [Means for solving the problem]

[0015] In order to achieve the above-mentioned object, the journal foil air bearing of the present invention is a journal foil air bearing for supporting a load applied along the radial direction of a rotating shaft rotating around a centerline, and includes: a top foil arranged to face the outer circumferential surface of the rotating shaft and arranged to surround the rotating shaft; a bump foil which is an elastically deformable member and arranged to surround the top foil; a base foil which is arranged to surround the bump foil and is a circular pipe member extending a predetermined length along the centerline, with a hollow formed therein with the center line as the center of the circle; and at least one anti-detachment portion provided on the base foil which restrains the bump foil accommodated in the hollow of the base foil from escaping along the longitudinal direction of the rotating shaft; and is characterized in that the anti-detachment portion protrudes a predetermined length toward the rotating shaft and has an end portion not contacting the surface of the rotating shaft.

[0016] Here, it is preferable that the end portion of the separation prevention portion is formed in a circular shape with the center line as the center of the circle.

[0017] Here, the base foil is preferably formed into a pipe shape with a C-shaped cross section by rolling a pressed rectangular metal sheet around a center line, and the detachment prevention portion is preferably formed by bending a protruding portion of the pressed metal sheet into a predetermined shape.

[0018] Here, it is preferable that the separation prevention portion is provided at each of both hollow ends of the base foil.

[0019] Here, it is preferable that a plurality of separation prevention portions are provided and spaced apart from each other at predetermined intervals along the circumferential direction of the base foil.

[0020] Here, it is preferable that the separation prevention portion protrudes toward the rotating shaft by a predetermined length and does not protrude further than the surface of the top foil facing the outer circumferential surface of the rotating shaft.

[0021] Here, it is preferable to provide a joining means for joining one end of the top foil, one end of the bump foil, one end of the base foil, and the other end of the base foil to one another.

[0022] Here, it is preferable that at least one of the top foil, the bump foil, and the base foil has a shape that can be mass-produced by press working. Effect of the Invention

[0023] According to the present invention, there is provided a journal foil air bearing for supporting a load applied in the radial direction of a rotating shaft rotating about a centerline, the journal foil air bearing including: a top foil arranged to face the outer circumferential surface of the rotating shaft and arranged to surround the rotating shaft; a bump foil which is an elastically deformable member and arranged to surround the top foil; a base foil which is a circular pipe member arranged to surround the bump foil and extends a predetermined length along the centerline, and has a hollow formed therein with the center of the circle at the center line; and at least one detachment prevention portion which is provided on the base foil and restrains the bump foil accommodated in the hollow of the base foil so as not to detach along the longitudinal direction of the rotating shaft; the detachment prevention portion protrudes a predetermined length toward the rotating shaft and is arranged so that an end portion does not come into contact with the surface of the rotating shaft, thereby preventing the bump top foil from being pushed out in the longitudinal direction of the rotating shaft during operation, thereby preventing a decrease in the performance of the bearing, and preventing the pushed-out bump foil from coming into contact with other parts and causing serious secondary damage. [Brief description of the drawings]

[0024] [Figure 1] 1 is a perspective view of a journal foil air bearing according to one embodiment of the present invention. [Diagram 2] FIG. 2 is an exploded perspective view of the journal foil air bearing illustrated in FIG. 1. [Diagram 3] FIG. 2 is a front view of the journal foil air bearing illustrated in FIG. 1. [Figure 4]FIG. 4 is an enlarged view of portion “IV” of the journal foil air bearing shown in FIG. 3. [Diagram 5] FIG. 4 is an enlarged view of the “V” portion of the journal foil air bearing illustrated in FIG. 3. [Figure 6] FIG. 3 is a partially enlarged view of the base foil shown in FIG. 2. [Figure 7] 3 is a view showing a state in which the second top foil and the first top foil shown in FIG. 2 are joined together; [Figure 8] 3 is a partially enlarged view of the first top foil shown in FIG. 2. [Figure 9] 13 is a view showing a state in which a second top foil and a first top foil are combined according to a second embodiment of the present invention. [Figure 10] 10 is a partially enlarged view of the first top foil shown in FIG. 9. [Figure 11] FIG. 10 is a partial enlarged view of the second top foil shown in FIG. [Figure 12] 13 is a view showing a state in which a second top foil and a first top foil are joined together according to a third embodiment of the present invention. [Figure 13] 13 is a partially enlarged view of the first top foil shown in FIG. 12. [Figure 14] FIG. 13 is a partial enlarged view of the second top foil shown in FIG. 12. [Figure 15] 3 is a view showing the coupling member shown in FIG. 2; [Figure 16] 2 is a view showing a state in which the journal foil air bearing shown in FIG. 1 is mounted in a bearing housing and used; [Figure 17] 1 is a cross-sectional view showing a conventional journal foil air bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

[0026] Fig. 1 is a perspective view of a journal foil air bearing according to one embodiment of the present invention, and Fig. 2 is an exploded perspective view of the journal foil air bearing shown in Fig. 1. Fig. 3 is a front view of the journal foil air bearing shown in Fig. 1.

[0027] 1 to 3, a journal foil air bearing 100 according to a preferred embodiment of the present invention is a journal foil air bearing for supporting a load applied along the radial direction of a rotation axis F rotating around a center line C, and is configured to include a base foil 10, a bump foil 20, top foils 30, 40, 50, and a connecting means.

[0028] The base foil 10 is a circular pipe member manufactured by pressing a flexible and elastic thin metal plate as shown in FIG. 2, and includes a base foil main body 11, an insertion portion 12, a storage portion 13, an assembly direction identification groove 14, and a separation prevention portion 15.

[0029] In this embodiment, the base foil 10 is formed by rolling a pressed rectangular metal sheet around a center line C into a pipe shape having a C-shaped cross section.

[0030] The base foil body 11 is a circular pipe member extending a predetermined length along a center line C, and has a hollow H formed therein with the center line C being the center of the circle.

[0031] The base foil body 11 is disposed so as to surround a bump foil 20 (described later), whereby the bump foil 20 is housed in a hollow H of the base foil body 11 .

[0032] The insertion portion 12 is a portion formed at the left end portion of the base foil body 11 as shown in Figure 4, and in this embodiment, the left end portion of the base foil body 11 is bent into an L-shape and protrudes upward so as to be accommodated in the accommodating portion 13 described later.

[0033] The insert portion 12 is formed with four coupling holes 121 spaced apart at predetermined intervals along the center line C as shown in FIG.

[0034] The receiving portion 13 is a portion formed at the right end portion of the base foil body 11 as shown in FIG. 2, and includes a horizontal portion 131, a vertical portion 132, a coupling hole 133, and a receiving space .

[0035] The horizontal portion 131 is a rectangular portion located horizontally at the upper end of the right end portion of the base foil body 11 that is formed by bending the right end portion into a "∩" shape as shown in FIG.

[0036] As shown in FIG. 4, the vertical portions 132 extend vertically downward from both ends of the horizontal portion 131, and a pair of vertical portions 132 are provided and spaced apart from each other at a predetermined interval.

[0037] The coupling holes 133 are holes formed in each of the pair of vertical portions 132, four of which are spaced apart from each other along the center line C at predetermined intervals, as shown in FIG.

[0038] The coupling hole 133 is formed at a position corresponding to the coupling hole 121 formed in the insertion portion 12 .

[0039] The storage space 134 is a space provided on the lower side by folding the right end portion of the base foil body 11 into an "∩" shape as shown in Figure 4, and is open downward toward the center line C.

[0040] The accommodation space 134 is a space for accommodating the insertion portions 32 , 42 , 52 of the top foils 30 , 40 , 50 , the insertion portion 22 of the bump foil 20 , and the insertion portion 12 of the base foil 10 .

[0041] In this embodiment, the accommodating portion 13 protrudes in the radial direction from the outer circumferential surface of the base foil body 11 so as to be inserted into a housing groove P formed in the inner circumferential surface of the bearing housing S as shown in FIG.

[0042] The assembly direction identification groove 14 is an "L" shaped groove formed on the front end of the base foil 10 as shown in FIG. 1, and is a groove for preventing assembly and installation errors by workers when assembling or installing the bearing.

[0043] The detachment prevention portion 15 is a stopper that restrains the bump foil 20 housed in the hollow H of the base foil 10 so as not to detach along the longitudinal direction C of the rotation axis F, and is provided at least at one of both ends of the hollow H of the base foil 10.

[0044] In this embodiment, two detachment prevention portions 15 are provided at one end of the hollow H of the base foil 10 and two are provided at the other end of the hollow H of the base foil 10 as shown in FIG.

[0045] Here, the two separation prevention portions 15 at one end of the hollow H of the base foil 10 are spaced apart from each other at intervals of 180° along the circumferential direction of the base foil 10 .

[0046] In this embodiment, the separation prevention portion 15 provided at one end of the hollow H of the base foil 10 and the separation prevention portion 15 provided at the other end of the hollow H of the base foil 10 are positioned adjacent to each other.

[0047] Here, the longitudinal separation distance C between a pair of adjacent separation prevention portions 15 has the same value as the width of the bump foil 20 within a predetermined tolerance.

[0048] The detachment prevention portion 15 protrudes toward the rotation shaft F by a predetermined length H1 as shown in FIG. 5, and is provided so that the end portion 151 does not come into contact with the surface of the rotation shaft F.

[0049] In this embodiment, the separation prevention portion 15 does not protrude beyond the surface of the first top foil 50 that directly faces the outer circumferential surface of the rotating shaft F as shown in FIG.

[0050] In this embodiment, the end portion 151 of the separation prevention portion 15 is not formed linearly as shown in FIG. 5, but is formed in a circular shape with the center line C as the center of the circle.

[0051] In this embodiment, the separation prevention portion 15 is formed by forming a substantially rectangular protruding portion during the press working for forming the base foil body 11, and then bending the protruding portion by 90 degrees.

[0052] The bump foil 20 is a circular pipe member manufactured by pressing a flexible and elastic thin metal plate as shown in FIG. 2, and includes a bump foil body 21, an insertion portion 22, a connecting hole 23, and an assembly direction identification groove 24.

[0053] The bump foil body 21 is a circular pipe member extending a predetermined length along a center line C, and has a hollow H formed therein with the center line C as the center of the circle.

[0054] In this embodiment, the bump foil body 21 is formed by rolling a pressed rectangular metal sheet around a center line C into a pipe shape having a C-shaped cross section.

[0055] The bump foil body 21 is disposed so as to surround the top foils 30, 40, and 50 while being housed in the hollow H of the base foil 10.

[0056] The bump foil body 21 includes a wave-shaped portion in which a large number of peaks and valleys are alternately connected so that elastic deformation in the radial direction of the center line C is possible.

[0057] The insertion portion 22 is a portion formed at the right end portion of the bump foil main body 21 as shown in Figures 2 and 4, and in this embodiment, the right end portion of the bump foil main body 21 is bent into an L shape and protrudes upward so as to be accommodated in the accommodating portion 13 described later.

[0058] Hereinafter, the portion where the insertion portion 22 of the bump foil 20 and the insertion portions 32, 42, 52 of the top foils 30, 40, 50 described below are formed will be referred to as a "root portion."

[0059] The coupling holes 23 are a pair of holes spaced apart at a predetermined interval along the center line C as shown in FIG.

[0060] The assembly direction identification groove 24 is an "L" shaped groove formed at the front end of the bump foil 20 as shown in FIG. 1, and is a groove for preventing assembly and installation errors by workers when assembling or installing the bearing.

[0061] The assembly direction identification groove 24 is located at a position corresponding to the assembly direction identification groove 14 and has the same shape as the assembly direction identification groove 14 .

[0062] The left end of the bump foil body 21 is a free end that can move freely as shown in FIG.

[0063] In this embodiment, two bump foils 20 are provided, and are arranged overlapping each other as shown in FIG.

[0064] The top foils 30, 40, 50 are circular pipe members manufactured by pressing a flexible and elastic thin metal plate as shown in FIG. 2, and are members disposed in a position facing the outer circumferential surface of the rotating shaft F.

[0065] In this embodiment, the top foils 30 , 40 , 50 include a third top foil 30 , a second top foil 40 , and a first top foil 50 .

[0066] The third top foil 30 is a circular pipe member manufactured by pressing a flexible and elastic thin metal plate as shown in FIG. 2, and is arranged to face the outer peripheral surface of the second top foil 40. The third top foil 30 includes a top foil body 31, an insertion portion 32, a connecting hole 33, and an assembly direction identification groove 34.

[0067] The base foil 10, bump foil 20, and top foils 30, 40, 50 are made of thin metal sheets of the same material, and their respective thicknesses may be different from each other.

[0068] The top foil body 31 is a circular pipe member extending along the center line C by a predetermined length, and a hollow H with the center line C as the center of the circle is formed inside.

[0069] In this embodiment, the top foil body 31 is formed by winding a pressed rectangular thin metal sheet around the center line C into a pipe shape with a C-shaped cross section.

[0070] The top foil body 31 is arranged so as to surround the second top foil 40 in a state of being accommodated in the hollow H of the bump foil 20.

[0071] The insertion portion 32 is a portion formed at the left end of the top foil body 31 as shown in FIG. 4. In this embodiment, the left end of the top foil body 31 is bent in an L shape and protrudes upward so as to be accommodated in the accommodating portion 13 described later.

[0072] The coupling holes 33 are four holes spaced apart along the center line C at a predetermined interval as shown in FIG. 2, and are formed in the insertion portion 32.

[0073] The assembly direction identification groove 34 is an "L"-shaped groove formed at the front end of the third top foil 30 as shown in FIG. 1, and is a groove for preventing assembly and mounting mistakes by the operator during the assembly of the bearing or when mounting the bearing.

[0074] The assembly direction identification groove 34 has the same shape at a position corresponding to the assembly direction identification grooves 14, 24.

[0075] The right end of the top foil body 31 is a free end that can move freely as shown in FIG.

[0076] The second top foil 40 is a circular pipe member manufactured by pressing a flexible and elastic thin metal plate as shown in FIG. 2, and is a member disposed between the first top foil 50 and the third top foil 30.

[0077] The second top foil 40 includes a top foil body 41 , an insertion portion 42 , a coupling hole 43 , an assembly direction identification groove 44 , and a separation prevention portion coupling hole 45 .

[0078] The second top foil 40 has almost the same or corresponding configuration as the third top foil 30 described above, so only the differences between the two will be described below.

[0079] As shown in FIG. 2, the second top foil 40 has an insertion portion 42 formed at the right end portion of the top foil body 41 .

[0080] The second top foil 40 differs from the third top foil 30 in that the top foil body 41 has a relatively short length, and therefore the free end of the second top foil 40 is located on the opposite side to the insertion portion 42 .

[0081] The first top foil 50 is a circular pipe member manufactured by pressing a flexible and elastic thin metal plate as shown in FIG. 2, and is located between the rotating shaft F and the second top foil 40, so as to directly face the outer circumferential surface of the rotating shaft F.

[0082] The first top foil 50 includes a top foil body 51 , an insertion portion 52 , a coupling hole 53 , an assembly direction identification groove 54 , and a separation prevention portion 55 .

[0083] The first top foil 50 is coated with a coating material (not shown) containing polytetrafluoroethylene (PTFE) on the surface facing the outer circumferential surface of the rotating shaft F. Polytetrafluoroethylene (PTFE) is also known as Teflon (registered trademark).

[0084] The first top foil 50 has almost the same or corresponding configuration as the third top foil 30 described above, so only the differences between the two will be described below.

[0085] The separation prevention portion 55 is a stopper that restrains the first top foil 50 so as not to separate along the longitudinal direction of the rotation axis F, and at least one separation prevention portion 55 is provided on the first top foil 50.

[0086] The separation prevention portions 55 are provided at both ends of the hollow H of the first top foil 50 as shown in FIG.

[0087] In this embodiment, one separation prevention portion 55 is provided at each end of the hollow H of the first top foil 50 .

[0088] In this embodiment, the separation prevention parts 55 are provided on both sides of the free end of the top foil body 51 in order to maximize the separation prevention effect as shown in FIG.

[0089] In this embodiment, the anti-detachment portion 55 protrudes a predetermined length H2 toward the second top foil 40 as shown in Figure 4, and is restrained by the side surface of the root portion of the second top foil 40, thereby having a structure that prevents it from displacing in the longitudinal direction C of the rotation axis F.

[0090] In this embodiment, the separation prevention portion 55 is formed by forming a substantially rectangular protruding portion during the press working for forming the top foil body 51, and then bending the protruding portion at 90 degrees.

[0091] In this embodiment, the separation prevention portion 55 does not protrude beyond the outer periphery of the base foil 10 as shown in FIG. 4, and has a position and shape that does not contact the base foil 10 and the bump foil 20.

[0092] Here, the separation distance in the longitudinal direction C between the pair of separation prevention portions 55 has the same value as the width of the second top foil 40 within a predetermined tolerance.

[0093] The joining means is a means for joining the insert portions 32, 42, 52 of the top foils 30, 40, 50 accommodated in the accommodating portion 13 of the base foil 10, the insert portion 22 of the bump foil 20, and the insert portion 12 of the base foil 10 to the accommodating portion 13 of the base foil 10.

[0094] In this embodiment, the coupling means includes coupling holes 121 , 133 , 23 , 33 , 43 , 53 and coupling members 60 .

[0095] The coupling holes 121, 133, 23, 33, 43, and 53 have already been described, so a description thereof will be omitted.

[0096] 15, the connecting member 60 is a U-shaped thin plate member that is inserted into the connecting holes 121, 133, 23, 33, 43, 53 to fix the top foils 30, 40, 50, the bump foil 20, and the base foil 10 to one another. The connecting member 60 includes a body portion 61, a through portion 62, and a bent portion 63.

[0097] The main body portion 61 is a long, band-like portion and is disposed on the outer surface of the vertical portion 132 along the center line C.

[0098] The through portions 62 are portions that are inserted into the coupling holes 121 , 133 , 23 , 33 , 43 , and 53 , and are disposed on both ends of the main body portion 61 .

[0099] In this embodiment, the through portion 62 is a horizontal portion formed by bending the main body portion 61 into an "L" shape.

[0100] The bent portion 63 is a vertical portion formed by inserting the through-hole 62 into a pair of connecting holes 133 as shown in FIG. 4, and then bending the end of the through-hole 62 upward and plastically deforming it as shown in FIGS. 4 and 15.

[0101] The bent portion 63 is tightly attached to the outer surface of the vertical portion 132, so that the connecting member 60 is firmly connected to the receiving portion 13 without being separated from the receiving portion 13.

[0102] That is, first, the "-" shaped penetrating portion 62 is inserted sufficiently so that the main body portion 61 is in close contact with the outer surface of one of the vertical portions 132, and then the protruding end portion of the penetrating portion 62 is bent upward and plastically deformed to form the bent portion 63.

[0103] In this embodiment, the top foils 30, 40, 50, the bump foil 20 and the base foil 10 are automatically cut and folded by press working without using a welding process, and thus have a shape suitable for mass production.

[0104] Meanwhile, FIG. 9 shows a joint structure between a second top foil 40a and a first top foil 50a according to a second embodiment of the present invention.

[0105] As shown in FIG. 10, the first top foil 50a has a separation prevention portion 55a provided at the center of the terminal portion of the free end.

[0106] The separation prevention portion 55a of the first top foil 50a extends along the longitudinal direction of the rotation axis F, and is disposed on the front surface of the terminal portion of the free end of the first top foil 50a.

[0107] Here, the separation prevention portion 55a is also formed by forming a substantially rectangular protruding portion during the press working for forming the top foil body 51, and then bending the protruding portion at 90°.

[0108] In the root portion of the second top foil 40a, anti-separation portions coupling holes 45a that are detachably coupled to the anti-separation portions 55a are provided at corresponding positions and in corresponding shapes as shown in FIG. 11.

[0109] On the other hand, FIG. 12 shows the coupling structure between the second top foil 40b and the first top foil 50b, which is the third embodiment of the present invention.

[0110] On the first top foil 50b, as shown in FIG. 13, a pair of anti-separation portions 55b are provided on the front surface of the end portion of the free end.

[0111] The anti-separation portions 55b are arranged at both ends of the hollow H of the first top foil 50 in a state of being maximally separated from each other.

[0112] On the second top foil 40b, anti-separation portions coupling holes 45b that are detachably coupled to the anti-separation portions 55b are provided at corresponding positions and in corresponding shapes as shown in FIG. 14.

[0113] In this embodiment, the anti-separation portions coupling holes 45b have a U-shape by opening one end portion on the outside.

[0114] Hereinafter, an example of a method for assembling and attaching the journal foil air bearing 100 having the above-described configuration will be described.

[0115] First, with the coupling member 60 not attached, the base foil 10, the bump foils 20, and the top foils 30, 40, 50 are assembled as shown in FIG. 2. At this time, as shown in FIGS. 16 and 4, the first top foil 50 is arranged so as to face the outer peripheral surface of the rotating shaft F, the second top foil 40 is arranged so as to surround the first top foil 50, the third top foil 30 is arranged so as to surround the second top foil 40, two bump foils 20 are arranged so as to surround the third top foil 30, and the base foil 10 is arranged so as to surround the two bump foils 20.

[0116] When the base foil 10, the bump foil 20 and the top foils 30, 40 and 50 are assembled as shown in FIG. 3, the coupling holes 121, 133, 23, 33, 43 and 53 are aligned in a row as shown in FIG.

[0117] Next, the connecting member 60 as shown in FIG. 15 is inserted into the connecting hole 133, and then the end portion is bent to form the bent portion 63, so that the connecting member 60 is firmly connected and cannot be separated from the accommodating portion 13, thereby completing the assembly of the journal foil air bearing 100.

[0118] Here, as shown in FIG. 5, the anti-detachment portion 15 restrains both sides of the bump foil 20 so that the bump foil 20 accommodated in the hollow H of the base foil 10 does not detach in either direction along the longitudinal direction C of the rotation axis F.

[0119] As shown in FIG. 4, the free end of the first top foil 50 is restrained by the separation prevention portion 55 so as not to separate in either direction along the longitudinal direction of the rotation axis F.

[0120] Finally, the modularized journal foil air bearing 100 is inserted into a bearing housing S having a housing groove P on the upper end of the inner circumferential surface as shown in Fig. 16, completing the installation of the journal foil air bearing 100. At this time, the worker accurately identifies the installation position and direction of the bearing using the assembly direction identification grooves 14, 24, 34, 44, 54, and then simply installs the journal foil air bearing 100 into the bearing housing S by pushing it in along the center line C. Here, the receiving portion 13 is received in the housing groove P.

[0121] The journal foil air bearing 100 having the above-mentioned configuration is a journal foil air bearing for supporting a load applied along the radial direction of a rotating shaft F rotating about a center line C, and includes: top foils 30, 40, 50 arranged to face the outer circumferential surface of the rotating shaft F and arranged to surround the rotating shaft F; a bump foil 20 which is an elastically deformable member and arranged to surround the top foils 30, 40, 50; a circular pipe member arranged to surround the bump foil 20 and extending a predetermined length along the center line C, and an inner pipe member which is arranged to surround the bump foil 20 and extends a predetermined length along the center line C, and has a circle centered on the center line C. The bearing includes a base foil 10 having a hollow H formed therein; at least one anti-detachment portion 15 is provided in the base foil 10 and restrains the bump foil 20 housed in the hollow H of the base foil 10 so as not to detach along the longitudinal direction C of the rotating shaft F; the anti-detachment portion 15 protrudes a predetermined length H1 toward the rotating shaft F and is provided so that its end portion does not come into contact with the surface of the rotating shaft F. This has the advantage that the bump foil 20 is not pushed out in the longitudinal direction C of the rotating shaft F during operation, which does not reduce the performance of the bearing and does not cause serious secondary damage by contacting other parts.

[0122] Furthermore, the journal foil air bearing 100 has an advantage in that the end portion 151 of the anti-detachment portion 15 is circular with the center line C as the center of the circle, which reduces the possibility of the anti-detachment portion 15 coming into contact with the top foils 30, 40, 50 or the rotating shaft F.

[0123] In addition, the journal foil air bearing 100 has a base foil 10 formed by rolling a pressed rectangular metal sheet around a center line C into a pipe shape with a C-shaped cross section, and the anti-detachment portion 15 is formed by bending a protruding portion of the metal sheet that has been pressed into a predetermined shape, which has the advantage that the base foil 10 with the anti-detachment portion 15 can be mass-produced by press processing without using a welding process.

[0124] Furthermore, the journal foil air bearing 100 has anti-detachment portions 15 provided at both ends of the hollow H of the base foil 10, which has the advantage that the bump foil 20 housed in the hollow H of the base foil 10 does not detach in either direction along the longitudinal direction C of the rotation axis F.

[0125] In addition, the journal foil air bearing 100 has a plurality of anti-detachment portions 15 spaced apart from each other at predetermined intervals along the circumferential direction of the base foil 10, which has the advantage that the anti-detachment portions 15 can evenly restrain the entire side of the bump foil 20.

[0126] Furthermore, in the journal foil air bearing 100, the anti-detachment portion 15 protrudes a predetermined length toward the rotating shaft F and does not protrude any further than the surface of the first top foil 50 that faces the outer circumferential surface of the rotating shaft F, which has the advantage that the anti-detachment portion 15 does not damage the rotating shaft F or generate noise.

[0127] In addition, since the journal foil air bearing 100 is provided with connecting means for connecting one end of the top foils 30, 40, 50, one end of the bump foil 20, one end of the base foil 10, and the other end of the base foil 10 to one another, it is easy to pre-assemble and modularize into a single unit, and the work of attaching or disassembling it to the bearing housing S at the work site is very simple, which has the advantage that the bearing can be easily stored and managed.

[0128] Furthermore, the journal foil air bearing 100 has an advantage in that at least one of the top foils 30, 40, 50, the bump foil 20, and the base foil 10 has a shape that can be mass-produced by press processing, making it more suitable for mass production than methods that use welding or other methods.

[0129] In addition, the journal foil air bearing 100 has the advantage that the base foil 10 serves to hold the outer shapes of the bump foil 20 and the top foils 30, 40, 50. Since the inner peripheral surface of the base foil 10 is made of a smooth thin plate, the shape tolerance and the surface frictional force maintain excellent values compared to the inner peripheral surface of the bearing housing S. Therefore, as shown in FIG. 17, even if the surface machining state of the inner surface of the bearing housing S is not good, compared with the conventional journal foil air bearing 1 in which the inner peripheral surface of the bearing housing S is in direct contact with the bump foil 3, the bearing can be easily mounted and has little influence on the performance of the bearing.

[0130] And the journal foil air bearing 100 has the advantage that the accommodating portion 13 includes an accommodating space 134 formed by bending one end portion of the base foil 10 in a '∩' shape, so that the base foil 10 can be mass-produced by pressing without using a welding process.

[0131] Also, the journal foil air bearing 100 includes insertion portions 12, 22, 32, 42, 52 formed by bending one end portions of the top foils 30, 40, 50, one end portion of the bump foil 20, and the other end portion of the base foil 10 in an L shape so as to be accommodated in the accommodating portion 13. Therefore, the insertion portions 12, 22, 32, 42, 52 can be mass-produced by pressing without using a welding process, and the insertion portions 12, 22, 32, 42, 52 can be easily accommodated in the accommodating portion 13.

[0132] And the journal foil air bearing 100 has the advantage that since the accommodating portion 13 protrudes radially from the outer peripheral surface of the base foil 10, by inserting the accommodating portion 13 into the housing groove P formed in the bearing housing S, it can be attached to the bearing housing S with accurate direction and depth.

[0133] The journal foil air bearing 100 is a journal foil air bearing for supporting a load applied along the radial direction of a rotational shaft F rotating about a center line C, and includes a first top foil 50 arranged to face the outer circumferential surface of the rotational shaft F and to surround the rotational shaft F; a second top foil 40 arranged to surround the first top foil 50; a bump foil 20 which is an elastically deformable member and arranged to surround the second top foil 40; a base foil 10 arranged to surround the bump foil 20; At least one of the anti-detachment portions 55 is provided on each top foil 50 and prevents the first top foil 50 from detaching along the longitudinal direction C of the rotation axis F. The anti-detachment portion 55 protrudes toward the second top foil 40 by a predetermined length H2 and is restrained by the second top foil 40 so as not to be displaced in the longitudinal direction of the rotation axis F. This has the advantages that the first top foil 50 is not pushed out in the longitudinal direction C of the rotation axis F during operation, the bearing performance is not reduced, and the pushed-out first top foil 50 does not come into contact with other parts and cause serious secondary damage.

[0134] In addition, the journal foil air bearing 100 has a first top foil 50 formed in the shape of a pipe with a C-shaped cross section by rolling a pressed rectangular metal sheet around a center line C, and the separation prevention portion 55 formed by bending a protruding portion of the metal sheet that has been pressed into a predetermined shape, which has the advantage that the first top foil 50 with the separation prevention portion 55 can be mass-produced by press processing without using a welding process.

[0135] In addition, the journal foil air bearing 100 has anti-detachment portions 55 provided at both ends of the hollow H of the first top foil 50, which has the advantage that the terminal end, which is the free end of the first top foil 50, will not detach in either direction along the longitudinal direction C of the rotation axis F.

[0136] Furthermore, in the journal foil air bearing 100, the anti-detachment portion 55 protrudes a predetermined length H2 toward the second top foil 40 and does not protrude any further than the outer peripheral surface of the base foil 10, which has the advantage that the anti-detachment portion 55 does not come into contact with the base foil 10 or the bearing housing S during bearing operation.

[0137] In addition, since the journal foil air bearing 100 is configured so that the anti-detachment portion 55 does not come into contact with the base foil 10 and the bump foil 20, there is an advantage that the anti-detachment portion 55 does not damage the base foil 10 and the bump foil 20 or generate noise during bearing operation.

[0138] Furthermore, the journal foil air bearing 100 is provided on the second top foil 40a, 40b and may include anti-detachment part connection holes 45a, 45b that can be freely detachably connected to the anti-detachment parts 55a, 55b, which has the advantage that the positions of the anti-detachment parts 55a, 55b can be set other than on both end side surfaces of the end part of the first top foil 50.

[0139] In addition, the journal foil air bearing 100 has an anti-detachment part connecting hole 45a provided in the center of one end of the second top foil 40a, as shown in Figure 9, which has the advantage that the end of the first top foil 50 can be restrained in both directions with only one anti-detachment part 55a.

[0140] In addition, the journal foil air bearing 100 has anti-detachment part connection holes 45b provided at both ends of the hollow H of the second top foil 40, one side of which is open, which has the advantage that the end portion of the first top foil 50 and the root portion of the second top foil 40 can be more firmly connected than in the case where only one anti-detachment part 55a is used.

[0141] In this embodiment, one anti-detachment portion 55 is provided at each end of the hollow H at the end portion of the first top foil 50, but it goes without saying that multiple anti-detachment portions 55 may be provided at each end of the hollow H of the first top foil 50, spaced apart from each other at predetermined intervals along the circumferential direction of the first top foil 50.

[0142] Although the present invention has been described above, it is apparent that the technical scope of the present invention is not limited to the contents described in the above embodiments, and that equivalent configurations modified or changed by a person having ordinary knowledge in the art do not depart from the technical idea of ​​the present invention.

Claims

1. 1. A journal foil air bearing for supporting a load applied along a radial direction of a rotating shaft rotating about a centerline, comprising: A top foil is disposed so as to face an outer circumferential surface of the rotating shaft and surround the rotating shaft; a bump foil that is an elastically deformable member and is disposed so as to surround the top foil; A base foil is a circular pipe member that is arranged to surround the bump foil and extends a predetermined length along the center line, and has a hollow formed therein with the center line being the center of a circle; At least one of the bump foils is provided on the base foil, and the bump foil is accommodated in the hollow of the base foil. The bump foil includes a detachment prevention portion that prevents the bump foil from detaching along the longitudinal direction of the rotation shaft. The detachment prevention portion protrudes toward the rotating shaft by a predetermined length and is provided so that an end portion does not contact a surface of the rotating shaft, A journal foil air bearing, characterized in that the anti-detachment portion protrudes a predetermined length toward the rotating shaft and does not protrude any further than the surface of the top foil that faces the outer circumferential surface of the rotating shaft.

2. 2. The journal foil air bearing according to claim 1, wherein an end portion of the anti-detachment portion is formed in a circular shape with the center line as a center of the circle.

3. The base foil is formed into a pipe shape having a C-shaped cross section by rolling a pressed rectangular metal sheet around the center line.

2. The journal foil air bearing according to claim 1, wherein the separation prevention portion is formed by bending a protruding portion of the rectangular thin metal plate which has been pressed into a predetermined shape.

4. 2. The journal foil air bearing according to claim 1, wherein the separation prevention portion is provided at each of both hollow ends of the base foil.

5. The journal foil air bearing according to claim 1 , wherein a plurality of the separation prevention portions are provided, the separation prevention portions being spaced apart from each other at predetermined intervals along the circumferential direction of the base foil.

6. 2. The journal foil air bearing according to claim 1, further comprising a connecting means for connecting one end of the top foil, one end of the bump foil, one end of the base foil, and the other end of the base foil to one another.

7. 2. The journal foil air bearing according to claim 1, wherein at least one of the top foil, the bump foil, and the base foil has a shape that can be mass-produced by pressing.

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