Air foil bearing and compressor including the air foil bearing

Abstract

To provide an air foil bearing that exhibits excellent performance even with a simpler structure than the related art.SOLUTION: An air foil bearing includes: a beam plate 100 provided in a lower portion thereof; a shim sheet provided on the beam plate and partially covering a top surface of the beam plate; and a top foil 300 provided on the shim sheet; where one side of the beam plate is fixed, and the other side of the beam plate is movable in the vertical direction.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an air foil bearing having a novel structure and a compressor including the air foil bearing.

Background Art

[0002] A bearing is a structure that belongs to a rotating body and supports it so as to rotate. There are various types of bearings such as ball bearings, journal bearings, and air foil bearings. Among these, an air foil bearing is composed of a base plate, bump foils, and a top foil. By forming an air film between the rotating body and the air foil bearing due to the rotation of the rotating body, cooling and support of the rotating body can be performed. Such air foil bearings are used in various industrial sites. For example, an air foil bearing can be used in a compressor for providing compressed air to a fuel cell.

[0003] More specifically, according to the conventional technology, when the pressure around the air foil bearing changes due to the flow of air caused by the rotation of the rotating body, the top foil pressurizes the bump foils, and thereby the shape of the pressurized bump foils changes. Then, when the rotation of the rotating body stops, the bump foils return to their original shapes. That is, according to the conventional technology, the bump foils have an elastic structure in which the shape changes reversibly by an external force.

[0004] For this reason, according to the conventional technology, the bump foils had an embossing structure with a surface having irregularities. Such a structure of the bump foils for embodying the elastic structure has acted as a factor increasing the time required to manufacture the air foil bearing.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Accordingly, the problem to be solved by the present invention is to provide an air foil bearing having a simpler structure than the conventional technology and exhibiting excellent performance, and equipment equipped with such an air foil bearing.

Means for Solving the Problem

[0006] According to one aspect of the present invention for achieving the above object, there is provided an air foil bearing including a beam plate provided at a lower portion, one side of the beam plate being fixed, and the other side of the beam plate being provided so as to be movable in the vertical direction.

[0007] It may further include a shim sheet provided on the upper portion of the beam plate and provided so as to cover a part of the upper surface of the beam plate.

[0008] It may further include a top foil provided on the upper portion of the shim sheet.

[0009] A plurality of the shim sheets may be provided, and the plurality of shim sheets may be provided along the periphery of the upper surface of the beam plate.

[0010] The outer peripheral edge of the beam plate has a circular shape, a through hole is formed in the central region of the beam plate, and the beam plate includes a peripheral region that forms the periphery of the beam plate and extends along the circumferential direction A of the circle, a separation region provided between the through hole and the peripheral region and separated from the peripheral region in the radial direction R of the circle, and a connection region that connects the peripheral region and the separation region.

[0011] The shim sheet may include a first region provided on the upper portion of the peripheral region of the beam plate, a second region connected to the first region and provided on the upper portions of the separation region and the connection region of the beam plate, and a third region connected to the second region and provided on the upper portion of the separation region.

[0012] The third region may include a plurality of protrusions extending in the circumferential direction A of the circle.

[0013] The plurality of protrusions may be arranged so as to be spaced apart from each other in the radial direction R of the circle between the plurality of protrusions.

[0014] Among the plurality of protrusions, the protrusion provided on the outer side in the radial direction R of the circle may be formed longer than the protrusion provided on the inner side in the radial direction R of the plurality of protrusions.

[0015] The width of the connecting region in the circumferential direction A of the circle may be the same as the width of the portion provided between the peripheral region and the separation region of the second region in the circumferential direction A of the circle.

[0016] The thickness of the beam plate may be 0.8 mm or more and 3.5 mm or less.

[0017] The top foil may include a peripheral portion provided on the upper portion of the peripheral region of the beam plate, an inner portion provided so as to be separated from the inner side of the peripheral portion in the radial direction R, and provided on the upper portion of the separation region of the beam plate, and a first connecting portion provided on the upper portion of the connecting region of the beam plate for connecting the peripheral portion and the inner portion.

[0018] The inner portion may include a plurality of inner members spaced apart from each other along the circumferential direction A, and the top foil may further include a second connecting portion for connecting the plurality of inner members to each other.

[0019] The width of the first connecting portion in the circumferential direction A of the circle may be smaller than the width of the connecting region in the circumferential direction A of the circle.

[0020] According to another aspect of the present invention for achieving the above object, there is provided a compressor including a housing and an air foil bearing coupled to one surface of the housing, wherein the air foil bearing includes a beam plate partially coupled to the one surface of the housing, and the beam plate includes a fixed end region fixed to the housing and a free end region capable of relative movement with respect to the housing.

[0021] It may further include a shim sheet provided to face the housing with the beam plate interposed therebetween and provided to cover a part of the upper surface of the beam plate.

[0022] It may further include a top foil provided to face the beam plate with the shim sheet interposed therebetween.

[0023] The outer peripheral edge of the beam plate has a circular shape, a through hole is formed in a central region of the beam plate, and the beam plate includes a peripheral region forming the peripheral edge of the beam plate and extending along a circumferential direction A of the circle, a separation region provided between the through hole and the peripheral region and separated from the peripheral region in a radial direction R of the circle, and a connection region connecting the peripheral region and the separation region, wherein the fixed end region is the peripheral region, and the free end region may be the separation region and the connection region.

[0024] The shim sheet may include a first region facing the peripheral region of the beam plate, a second region connected to the first region and facing the separation region and the connection region of the beam plate, and a third region connected to the second region and facing the separation region.

[0025] It may further include a rotating part provided to face a side opposite to a side facing the housing of both surfaces of the air foil bearing, and the rotating part may be provided to face the separation region.

[0026] The rotating part may be provided so as to be separated from the peripheral region in the radial direction of the rotating part.

[0027] The free end region is separated from the housing in the longitudinal direction of the rotating part, so that the free end region can bend in the housing direction.

Advantages of the Invention

[0028] According to the present invention, an air foil bearing having a simpler structure than the prior art and exhibiting excellent performance can be manufactured, and equipment equipped with such an air foil bearing can be manufactured.

Brief Description of the Drawings

[0029]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Modes for Carrying Out the Invention

[0030] Hereinafter, with reference to the drawings, the air foil bearing and the compressor according to the present invention will be described.

[0031] Air foil bearing FIG. 1 is a plan view showing the laminated structure of the air foil bearing according to the present invention, and FIG. 2 is a plan view showing the laminated structure of the beam plate and the shim sheet in the air foil bearing according to the present invention. And FIG. 3 is a view showing the structure of a partial region of the beam plate of the air foil bearing according to the present invention and the displacement amount for each region of the beam plate in color.

[0032] Referring to FIGS. 1 to 3, the air foil bearing 10 according to the present invention can have a structure in which a plurality of different components are laminated upward. More specifically, the air foil bearing 10 may include a beam plate 100 provided at the lower part of the air foil bearing, a shim sheet 200 laminated and provided on the upper part of the beam plate 100 and provided so as to cover a part of the upper surface of the beam plate 100, and a top foil 300 provided on the upper part of the shim sheet 200. That is, the air foil bearing 10 according to the present invention may have a structure in which the beam plate 100, the shim sheet 200, and the top foil 300 are sequentially laminated from below upward. On the other hand, according to the present invention, the beam plate 100, the shim sheet 200, and the top foil 300 constituting the air foil bearing 10 can all have smooth surfaces. Therefore, according to the present invention, a separate process for forming a concavo-convex surface, that is, an embossing structure, is not required to manufacture the air foil bearing 10. At this time, whether or not it has a smooth surface can be determined based on human visual inspection.

[0033] As can be understood from the name, according to the present invention, the thicknesses of the shim sheet 200 and the top foil 300 may be significantly thinner compared to the thickness of the beam plate 100. Therefore, the physical rigidity of the shim sheet 200 and the top foil 300 may also be significantly weaker compared to the rigidity of the beam plate 100. As will be described later, the beam plate 100 may be configured to be able to flex reversibly in response to a pressure change around the beam plate. For this reason, the thickness of the beam plate 100 may be 0.8 mm or more and 3.5 mm or less. When the thickness of the beam plate 100 is less than 0.8 mm, the rigidity of the beam plate 100 becomes excessively weak, so problems may occur in the durability of the air foil bearing 10. When the thickness of the beam plate 100 exceeds 3.5 mm, the beam plate 100 may not flex sufficiently in response to a pressure change.

[0034] On the other hand, as shown in FIGS. 1 and 2, the outer peripheries of the beam plate 100 and the top foil 300 may have a circular shape, and a through hole H may be formed in the central region of the beam plate 100 and the top foil 300. Also, the beam plate 100 and the top foil 300 may each consist of one configuration.

[0035] On the contrary, as shown in FIG. 2, a plurality of shim sheets 200 may be provided. FIG. 2 shows, as an example, a state in which six shim sheets 200 are provided at equal intervals along the periphery of the upper surface of the beam plate 100. More specifically, the plurality of shim sheets 200 may be arranged so as to be separated from each other along the circumferential direction A of the circle.

[0036] On the other hand, referring to FIGS. 2 and 3, the beam plate 100, the shim sheet 200, and the top foil 300 that constitute the air foil bearing 10 may each be divided into a plurality of regions. Hereinafter, a plurality of regions that constitute the beam plate 100, the shim sheet 200, and the top foil 300 will be considered.

[0037] Referring to FIGS. 2 and 3, the beam plate 100 may include a peripheral region 110 that forms the outer peripheral edge of the beam plate and extends along the circumferential direction A of the circle, a separation region 120 provided between the through hole H and the peripheral region 110 and separated from the peripheral region 110 in the radial direction R of the circle, and a connection region 130 that connects the peripheral region 110 and the separation region 120.

[0038] Also referring to FIGS. 2 and 3, the shim sheet 200 may include a first region 210 provided on the upper part of the peripheral region 110 of the beam plate 100, a second region 220 connected to the first region 210 and provided on the upper parts of the separation region 120 and the connection region 130 of the beam plate 100, and a third region 230 connected to the second region 220 and provided on the upper part of the separation region 120.

[0039] At this time, the third region 230 may include a plurality of protrusions 232 extending in the circumferential direction A. At this time, the plurality of protrusions 232 may be arranged so as to be separated from each other in the radial direction R between the plurality of protrusions 232. In FIG. 2, as an example, a state in which three protrusions 232 are arranged so as to be separated from each other in the radial direction R in the third region 230 of the plurality of shim sheets 200 is shown.

[0040] Continuing to refer to FIG. 2, the lengths of the plurality of protrusions 232 provided in the third region 230 of the shim sheet 200 may be different from each other. This can mean that the length in the circumferential direction A of any one of the plurality of protrusions 232 is different from the length in the circumferential direction A of any other one of the plurality of protrusions 232.

[0041] More specifically, according to the present invention, the protrusion provided on the outer side in the radial direction R among the plurality of protrusions 232 may be formed longer than the protrusion provided on the inner side in the radial direction R among the plurality of protrusions 232. Therefore, according to the present invention, the protrusion provided on the outer side in the radial direction R can be longer.

[0042] Also, referring to FIG. 1, the top foil 300 may include a peripheral portion 310 provided above the peripheral region 110 of the beam plate 100, an inner portion 320 provided so as to be spaced inside the peripheral portion 310 in the radial direction R and above the spaced region 120 of the beam plate 100, and a first connecting portion 330 that connects the peripheral portion 310 and the inner portion 320 and is provided above the connecting region 130 of the beam plate 100. At this time, the inner portion 320 may include a plurality of inner members 322 spaced apart from each other along the circumferential direction A. In FIG. 1, as an example, a configuration in which the inner portion 320 is composed of six inner members 322 is shown. More preferably, the peripheral portion 310 may be provided above the first region 210 of the shim sheet 200 and the peripheral region 110 of the beam plate 100 so as to face the first region 210 of the shim sheet 200 and the peripheral region 110 of the beam plate 100. Also, the inner portion 320 may be provided so as to face the second region 220 and the third region 230 of the shim sheet 200 and the spaced region 120 of the beam plate 100. Also, the number of the inner members 322 may be the same as the number of the shim sheets 200.

[0043] Also, the top foil 300 may further include a second connecting portion 340 that connects the plurality of inner members 322 to each other. That is, according to the present invention, the peripheral portion 310 and the inner portion 320 that occupy most of the size of the top foil 300 may be spaced apart from each other in the radial direction R, and the configuration of the inner portion 320 (that is, the inner members) may be spaced apart from each other in the circumferential direction A. However, the top foil 300 can be formed into one configuration by the first connecting portion 330 that connects the peripheral portion 310 and the inner portion 320 and the second connecting portion 340 that connects the plurality of inner members 322 to each other.

[0044] On the other hand, referring to FIGS. 1 to 3, the width of the connecting region 130 of the beam plate 100 in the circumferential direction A may be the same as the width of the portion provided between the peripheral region 110 and the spaced region 120 in the second region 220 of the shim sheet 200 in the circumferential direction A. Therefore, as shown in FIG. 1, the entire connecting region 130 may be overlapped by the second region 220.

[0045] Also, referring to FIGS. 1 to 3, the width of the first connecting portion 330 of the top foil 300 in the circumferential direction A may be smaller than the width of the connecting region 130 in the circumferential direction A, and the width of the first connecting portion 330 of the top foil 300 in the circumferential direction A may be smaller than the width of the portion provided between the peripheral region 110 and the separated region 120 in the circumferential direction A of the second region 220. Therefore, as shown in FIG. 1, when the air foil bearing 10 according to the present invention is viewed from above, the first connecting portion 330 may cover only a part of the second region 220.

[0046] Compressor FIG. 4 is a cross-sectional view showing the structure of a compressor according to the present invention, and FIG. 5 is a cross-sectional view showing the arrangement relationship among the air foil bearing, the housing, and the rotating portion in the compressor according to the present invention.

[0047] As shown in FIG. 4, the compressor according to the present invention may include a housing 20 forming at least a part of the outer surface of the compressor, and an air foil bearing 10 coupled to one surface of the housing 20. FIG. 4 shows a state where the air foil bearing 10 is coupled to the inner surface of the housing 20.

[0048] At this time, referring to FIGS. 1 to 3, the air foil bearing 10 may include a beam plate 100, a part of which is coupled to one surface of the housing 20, a shim sheet 200 provided to face the housing 20 with the beam plate 100 interposed therebetween, and a top foil 300 provided to face the beam plate 100 with the shim sheet 200 interposed therebetween and covering a part of the upper surface of the beam plate 100. For example, one or more through regions may be formed in the peripheral region 110 (see FIG. 3) of the beam plate 100, and the beam plate 100 and the housing 20 may be coupled to each other by bolts being coupled to the through regions.

[0049] Based on the above-described content, let's consider the air foil bearing and compressor according to the present invention.

[0050] In the air foil bearing 10 according to the present invention, one side of the beam plate 100 may be fixed, and the other side of the beam plate 100 may be provided so as to be movable in the vertical direction, that is, in the direction of protruding from or entering the ground with reference to FIG. 1.

[0051] More specifically, as shown in FIG. 5, the beam plate 100 may include a fixed end region E fixed to the housing 20 of the compressor according to the present invention, and a free end region F capable of relative movement with respect to the housing 20. More preferably, the fixed end region E may be the peripheral region 110 (see FIG. 3) of the beam plate, and the free end region F may be the separated region 120 (see FIG. 3) and the connecting region 130 (see FIG. 3) of the beam plate. On the other hand, FIG. 5 shows a case where the housing 20 faces the free end region F of the beam plate 100. However, differently, the housing 20 may not face the free end region F of the beam plate 100. For example, the housing 20 may face only the fixed end region E of the beam plate 100.

[0052] Continuing to refer to FIGS. 4 and 5, the compressor according to the present invention may further include a rotating part 30 provided so as to face the opposite side of the side of the air foil bearing 10 that faces the housing 20 among both sides. At this time, as shown in FIG. 5, the rotating part 30 may be provided so as to face the separated region 120 (see FIG. 3) of the beam plate 100 (see FIG. 3) with a shim sheet and a top foil interposed therebetween.

[0053] More specifically, the rotating part 30 may include a shaft 32 provided at the center of the rotating part, and an extension part 34 extending in the radial direction of the shaft 32 from the shaft 32. At this time, the separated region 120 (see FIG. 3) may be provided so as to face the extension part 34.

[0054] On the one hand, as shown in FIG. 5, the rotating part 30 may be provided so as to be separated from the peripheral region 110 (see FIG. 3) in the radial direction of the rotating part. More specifically, the extension part 34 of the rotating part 30 may be provided so as to be separated from the peripheral region of the beam plate.

[0055] Also, as shown in FIG. 5, the free end region F of the beam plate 100 may be separated from the shaft 32 in the radial direction of the rotating part 30. Therefore, a predetermined empty space may be formed between the free end region F and the shaft 32. Moreover, the free end region F of the beam plate 100 may be separated from the housing 20 in the longitudinal direction of the rotating part 30. Therefore, a predetermined empty space may be formed between the free end region F and the housing 20. In this case, the free end region F can be smoothly bent in the direction of the housing 20 (the right side direction based on FIG. 5).

[0056] FIG. 6 is a schematic side sectional view showing the shape of the air foil bearing when the rotating part of the compressor according to the present invention does not rotate, and FIG. 7 is a schematic side sectional view showing the shape of the air foil bearing when the rotating part of the compressor according to the present invention rotates.

[0057] Hereinafter, with reference to FIGS. 6 and 7, the shape change of the air foil bearing according to the operating state of the compressor according to the present invention will be described.

[0058] When the rotating part 30 of the compressor does not rotate, as shown in FIG. 6, the entire region of the beam plate 100 of the air foil bearing is provided side by side with the rotating part 30 without being bent.

[0059] Thereafter, when the rotating part 30 of the compressor rotates, air will flow between the rotating part 30 and the air foil bearing, thereby increasing the pressure between the rotating part 30 and the air foil bearing, and thereby the air foil bearing will receive a force in the opposite direction to the direction facing the rotating part 30 (downward based on FIG. 7).

[0060] However, as described above, the peripheral region 110 of the beam plate 100 may be a fixed end region E coupled to the housing 20, and the spaced-apart region 120 and the connection region 130 of the beam plate 100 may be free end regions F not coupled to the housing 20. Therefore, even when the air foil bearing receives a force in the direction opposite to the direction in which it faces the rotating part 30, the shape of the fixed end region E is not deformed, while the shape of the free end region F is deformed and bent. However, due to the rigidity of the beam plate 100 itself, the free end region F will bend only up to the point where a force balance is formed between the pressure due to the air flow and the restoring force of the beam plate 100. After that, when the rotation of the rotating part 30 of the compressor stops, due to the elasticity of the beam plate 100, it will return to its original state again as shown in FIG. 6.

[0061] According to the present invention, without forming an embossing structure with uneven surfaces due to reversible shape deformation by an external force, while using the rigidity of the beam plate 100 itself, by distinguishing the beam plate 100 into a fixed end region and a free end region, the function of the air foil bearing can be exerted. On the other hand, the compressor according to the present invention may be a compressor for providing compressed air to a fuel cell.

[0062] As described above, even if the present invention is described by way of limited embodiments and drawings, the present invention is not limited thereby, and it goes without saying that various implementations are possible within the equivalent scope of the technical idea and claims of the present invention by those having ordinary knowledge in the technical field to which the present invention pertains.

Explanation of Reference Numerals

[0063] 10: Air foil bearing 20: Housing 30: Rotating part 32: Shaft 34: Extension part 100: Beam plate 110: Peripheral region 120: Spaced-apart region 130: Connection region 200: Shim Sheet 210: First Region 220: Second Region 230: Third Region 232: Protrusion 300: Top Foil 310: Peripheral Portion 320: Inner Portion 322; Inner Member 330: First Connecting Portion 340: Second Connecting Portion H: Through-Hole A: Circumferential Direction R: Radial Direction E: Fixed-End Region F: Free-End Region

Claims

1. a beam plate provided at the lower part, a plurality of shim sheets provided on the upper part of the beam plate and configured to cover a part of the upper surface of the beam plate, a top foil provided on the upper part of the shim sheet, and including, one side of the beam plate is fixed, and the other side of the beam plate is provided to be movable in the vertical direction, the plurality of shim sheets are provided along the periphery of the upper surface of the beam plate, the plurality of shim sheets are arranged to be spaced apart from each other along the circumferential direction A of the beam plate, an air foil bearing.

2. the outer peripheral edge of the beam plate has a circular shape, a through hole is formed in the central region of the beam plate, the beam plate, a peripheral region forming the periphery of the beam plate and extending along the circumferential direction A, a separation region provided between the through hole and the peripheral region and separated from the peripheral region in the radial direction R of the beam plate, a connecting region connecting the peripheral region and the separation region, the air foil bearing according to claim 1.

3. the shim sheet, a first region provided on the upper part of the peripheral region of the beam plate, a second region connected to the first region and provided on the upper parts of the separation region and the connecting region of the beam plate, a third region connected to the second region and provided on the upper part of the separation region, the air foil bearing according to claim 2.

4. the third region includes a plurality of protrusions extending in the circumferential direction A, the air foil bearing according to claim 3.

5. between the plurality of protrusions, the plurality of protrusions are arranged to be spaced apart from each other in the radial direction R, the air foil bearing according to claim 4.

6. among the plurality of protrusions, the protrusion provided on the outer side in the radial direction R is formed longer than the protrusion provided on the inner side in the radial direction R among the plurality of protrusions, the air foil bearing according to claim 5.

7. the width of the connecting region in the circumferential direction A is the same as the width of the portion provided between the peripheral region and the separation region in the circumferential direction A of the second region, the air foil bearing according to claim 3.

8. The air foil bearing according to claim 1, wherein the thickness of the beam plate is 0.8 mm or more and 3.5 mm or less.

9. The top foil includes a peripheral portion provided on the upper part of the peripheral region of the beam plate, an inner portion provided so as to be separated inside the peripheral portion in the radial direction R and provided on the upper part of the separated region of the beam plate, and a first connecting portion provided on the upper part of the connecting region of the beam plate and connecting the peripheral portion and the inner portion. The air foil bearing according to claim 3.

10. The inner portion includes a plurality of inner members separated from each other along the circumferential direction A, The air foil bearing according to claim 9, wherein the top foil further includes a second connecting portion that connects the plurality of inner members to each other.

11. The air foil bearing according to claim 9, wherein the width of the first connecting portion in the circumferential direction A is smaller than the width of the connecting region in the circumferential direction A.

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