Air foil bearing installation structure

Abstract

The present invention relates to an installation structure for an airfoil bearing, in which a spacer is provided at a bent portion of a foil assembly, a resilient locking piece is formed on the spacer, and a locking protrusion is formed on an inner wall surface of a slot formed in a housing to lock the locking piece, thereby preventing axial movement and separation of the foil assembly without the need for an additional component for blocking the entrance of the slot.

Description

[Technical Field]

[0001] The present invention relates to an installation structure for an airfoil bearing, and more particularly to an installation structure for an airfoil bearing that prevents the airfoil bearing from coming off in the axial direction. [Background technology]

[0002] An air compressor includes a rotor that is rotated by electromagnetic force and an impeller attached to the end of the rotor, and is capable of drawing in, compressing, and then discharging air by rotating the impeller at high speed.

[0003] On the other hand, bearings using rolling elements such as balls or rollers generate noise and vibration and require a separate lubricant, making them unsuitable for supporting rotors that rotate at high speeds.

[0004] For this reason, airfoil bearings that can support the load by air film (air pressure) are used.

[0005] 1, the airfoil bearing has a bump foil 20 provided along the inner circumferential surface of the hollow 11 of the housing 10 of the air compressor, and a top foil 30 disposed inside the bump foil 20. A rotor 40 is disposed inside the top foil 30, and the rotor 40 is configured to rotate with the inner circumferential surface of the top foil 30 and the outer circumferential surface of the rotor 40 spaced apart from each other.

[0006] The bump foil 20 and the top foil 30 have bent portions 21, 31 formed at their circumferential ends by bending them radially outward, and the bent portions 21, 31 are inserted into slots 13 formed in the housing 10, so that the bump foil 20 and the top foil 30 are fixed to the housing 10 without rotating in the circumferential direction.

[0007] However, when the rotor 40 rotates at high speed, misalignment caused by scattering of parts generates a force that pushes the bump foil 20 and top foil 30 in the axial direction, although the strength is slight. Therefore, a structure is required to prevent the foil assembly (referring to the bump foil and top foil collectively) from moving axially and from leaving its fixed position in the slot 13.

[0008] Therefore, conventionally, as shown in Figure 2(a), a pinhole 14 is formed at the top of the slot 13 of the housing 10, a pin 15 is press-fitted into the pinhole 14, and then the boundary of the pinhole 14 is crimped to prevent the pin 15 at the crimped portion (c) from coming off.

[0009] Therefore, the pin 15 blocks the axial movement of the folded portions 21, 31 of the foil assembly, thereby preventing the foil assembly from being separated.

[0010] 2(b), a seating groove 16 is formed around the front surface of the slot 13 of the housing 10, and a locking plate 17 is inserted and seated in the seating groove 16, and then the locking plate 17 is fixed to the housing 10 with screws 18. In this case, the locking plate 17 blocks the entrance of the slot 13, preventing the bent portions 21 and 31 of the foil assembly from moving out of the slot 13, and preventing the foil assembly from coming off.

[0011] However, the above-described installation structure has a problem in that the folding portions 21 and 31 can move circumferentially inside the slot 13, causing the foil assembly to move circumferentially, thereby reducing the stability of the installation state of the foil assembly and, therefore, reducing the support stability of the rotor 40.

[0012] Furthermore, in order to prevent the foil assembly from coming off in the axial direction, additional parts such as the pin 15, the locking plate 17, and the screw 18 are used, which increases the number of parts and the number of assembly steps, thereby increasing the assembly time and reducing productivity. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been devised to solve the above problems, and an object of the present invention is to provide an airfoil bearing mounting structure that can prevent circumferential movement and axial separation of the airfoil bearing, and that reduces the number of parts and assembly steps, thereby shortening assembly time, reducing manufacturing costs, and improving productivity. [Means for solving the problem]

[0014] To achieve the above object, the present invention provides a foil assembly in which a bump foil and a top foil are stacked in a cylindrical shape, a spacer attached to a bent portion formed to protrude radially from the foil assembly, and the foil assembly and the bent portion are inserted into a bearing installation hole and a slot formed in a housing of an air compressor, and a circumferential gap within the slot is eliminated by the spacer.

[0015] The spacer includes side plate portions and a connecting portion that connects the rear ends of the side plate portions, and the front portions of the side plate portions are cut in the longitudinal direction, and the upper portions of the cut lines are bent in both outward directions to form locking pieces.

[0016] The locking pieces have elasticity that allows them to regain their shape and recover in the inner and outer directions of the spacer.

[0017] The wall portions on both sides of the slot entrance are formed with receiving portions into which the locking pieces of the spacer are inserted, and the ends of the receiving portions on the slot entrance side are formed with locking protrusions to which the ends of the locking pieces are locked.

[0018] A plurality of fastening holes are formed in the bent portion of the foil assembly, and the same number of fastening holes are formed in both side plate portions of the spacer. Fastening members are installed through the fastening holes to fix the spacer to the bent portion.

[0019] The fastening member includes a base that is in close contact with one side of the spacer, an extension portion that is horizontally bent and extended from both sides of the upper end of the base and passes through the bent portion and the fastening hole of the spacer, and a locking portion that is bent downward at the end of the extension portion and is in close contact with the other side of the spacer.

[0020] The spacer may have an open front end and be axially sandwiched outside the folded portion of the foil assembly. [Effects of the Invention]

[0021] According to the present invention as described above, a spacer is provided at the folded portion of the foil assembly, so that no gap occurs between the folded portion of the bump foil and the folded portion of the top foil, and no gap exists between the folded portion and the slot.

[0022] Therefore, circumferential flow is prevented when the air foil bearing (foil assembly + spacer) is installed.

[0023] Meanwhile, a locking piece extending outward is formed at the end of the spacer, and a locking protrusion is formed inside a slot formed in the housing. When the spacer is inserted into the slot, the locking piece is locked onto the locking protrusion, preventing axial movement and separation of the airfoil bearing.

[0024] As described above, pins or locking plates are not used as in the past to prevent axial separation, so the number of parts does not increase, which reduces manufacturing costs and the number of assembly steps, and further improves productivity. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a cross-sectional view of an air foil bearing according to the prior art in an installed state. [Figure 2] 10(a) and 10(b) are diagrams illustrating a structure for preventing the airfoil bearing from coming off in the axial direction. [Figure 3] 1 is an exploded perspective view of an airfoil assembly according to the present invention; [Figure 4] FIG. 4 is an assembly diagram of FIG. 3. [Figure 5] FIG. 2 is a front view of an air foil bearing according to the present invention in an installed state. [Figure 6] 6 is a cross-sectional view taken along line AA in FIG. 5, showing a plan view of a bent portion of the airfoil bearing, a spacer, and both side walls of a slot formed in the housing. [Figure 7] FIG. 7 is a front view of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention can be modified in various ways and can have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to the specific embodiments, and it should be understood that the present invention includes all modifications, equivalents, and alternatives within the spirit and technical scope of the present invention. The thickness of lines and the size of components shown in the accompanying drawings may be exaggerated for the sake of clarity and convenience of explanation.

[0027] In addition, the terms used below are defined in consideration of the functions of the present invention and may vary depending on the intentions of the user or operator or legal precedents. Therefore, such terms should be defined based on the overall content of this specification.

[0028] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0029] As shown in FIGS. 3 and 4, an airfoil bearing, which is one configuration of an installation structure for an airfoil bearing according to the present invention, includes a foil assembly 100, a spacer 200, and a fastening member 300.

[0030] The foil assembly 100 has a cylindrical shape similar to that of the prior art, and is composed of a bump foil and a top foil overlapping each other in the radial direction. The top foil is located radially inward and formed in a simple cylindrical shape, supporting the load through an air film formed between it and the rotor. The bump foil protrudes radially and is formed with a concave-convex shape that is repeatedly formed in the circumferential direction, distributing and supporting the load transmitted from the top foil to the housing 10 between the inner circumferential surface of a bearing installation hole 11 formed in the housing 10 and the top foil.

[0031] Since the structure of the foil assembly 100 is the same as that of the prior art, the bump foil and top foil are not shown in detail, and only the overall shape (cylindrical shape) is shown. In the drawings, reference numeral 110 denotes a "bent portion" that is inserted into a slot 12 formed in the housing 10 to prevent the foil assembly 100 from moving in the circumferential direction.

[0032] The bent portion 110 is formed by overlapping the bent portion of the bump foil and the bent portion of the top foil, and a plurality of linear fastening holes 111 are formed at regular intervals in the axial direction, penetrating the bent portion 110 laterally.

[0033] The spacer 200 is a component that surrounds the outside of the bent portion 110 to clamp the bent portion of the bump foil and the bent portion of the top foil, and is sandwiched in the slot 12 formed in the bearing installation hole 11 to prevent any empty space from being present inside the slot 12, thereby preventing the bent portion 110 from moving left and right within the slot 12, i.e., in the circumferential direction of the bearing installation hole 11.

[0034] The spacer 200 includes two side plate portions 210 surrounding both side surfaces of the bent portion 110, and a connecting portion 220 connecting the rear end portions of the two side plate portions 210. JPEG0007781186000001.jpg11162 Therefore, the front end is open and can be pinched to the outside of the folding portion 110 through the opening.

[0035] In addition, the spacer 200 has a plurality of fastening holes 230 formed at regular intervals along the length of the spacer 200, penetrating both side plate portions 210. When the spacer 200 is sandwiched outside the bent portion 110, the fastening holes 111 of the bent portion 110 and the fastening holes 230 of the spacer 200 are aligned with each other.

[0036] The fastening member 300 includes a rectangular plate-shaped base 310, extensions 320 bent and extended from both sides of the upper end of the base 310 in one direction, and locking portions 330 formed by bending downwards at the end of each extension 320. The locking portions 330 are formed by bending the extensions 320 after they pass through the fastening holes 111 and 230 when the fastening member 300 is installed.

[0037] When the fastening is completed, the base 310 and the locking portion 330 are connected to the extension portion 320 and are tightly fitted and locked to the outer surfaces of the side plate portions 210 of the spacer 200, so that the fastening member 300 does not come off from the bending portion 110 and the spacer 200, thereby firmly fixing the spacer 200 so that it does not come off from the bending portion 110.

[0038] Meanwhile, locking pieces 240 are formed on both side plates 210 of the fastening member 300 at the end opposite to the connecting portion 220, i.e., the end on the opening side, and extend outward. The locking pieces 240 are formed by cutting the side plates 210 to a predetermined length in the length direction and bending the upper portions of the cut lines outward from the side plates 210, and are elastically deformable in the left and right lateral directions around the bent portions.

[0039] The airfoil bearing having the above-described structure is mounted in a housing 10 in a structure as shown in FIGS.

[0040] The housing 10 is formed with a circular bearing installation hole 11 into which the foil assembly 100 is inserted, and a slot 12 is formed on one circumferential side of the bearing installation hole 11, protruding radially and extending axially, having a length and width sufficient to accommodate the bent portion 110 and the spacer 200.

[0041] Therefore, the airfoil bearing is inserted into the bearing installation hole 11 and the slot 12 from the rear end (the end of the spacer 200 toward the connecting portion 220) in the assembled state as shown in FIG.

[0042] The airfoil bearing is shown fully inserted into the bearing mounting hole 11 and slot 12 of the housing 10 in FIG.

[0043] On the other hand, as shown in Figure 6, a concave accommodating section 10b for accommodating the locking piece 240 is formed on the inner surface of each side wall 10a of the slot 12 at the entrance side, and a locking protrusion 10c is formed at the entrance side end of the accommodating section 10b, which is perpendicular to the longitudinal direction of the slot 12 (the insertion direction of the spacer 200).

[0044] Therefore, when the spacer 200 attached to the bending portion 110 is inserted into the slot 12, the locking piece 240 narrows laterally inward as it passes through the entrance, and then expands laterally outward due to its elastic restoring force as it passes through the locking protrusion 10c, and is accommodated inside the accommodating portion 10b.

[0045] Therefore, when the airfoil bearing moves axially during high-speed rotation of the air compressor rotor, the locking pieces 240 on both sides of the spacer 200 are locked onto the locking protrusions 10c, thereby preventing the airfoil bearing from moving axially in the slots 12.

[0046] In addition, since the spacer 200 clamps the folded portion 110 of the foil assembly 100, no gap is generated between the bump foil and the folded portion of the top foil that constitute the folded portion 110, and the volume of the spacer 200 itself prevents any gap from being generated laterally (circumferentially around the bearing installation hole 11) inside the slot 12, thereby preventing circumferential movement of the airfoil bearing.

[0047] As described above, by preventing the circumferential movement and axial compression of the airfoil bearing, it is possible to more stably support the high-speed rotation of the rotor and reliably prevent the airfoil bearing from coming off the slot.

[0048] In particular, the present invention achieves the object through a simple structural change in which a locking plate 240 is formed on the spacer 200, which is one component of the airfoil bearing, and a locking protrusion 10c is formed on the inner wall of the slot 12. This eliminates the need to provide a pin or locking plate at the entrance of the slot, as in the conventional method, to prevent the bent portion 110 from coming off in the axial direction, and also eliminates the need for additional work such as crimping or bolting. This has the effect of not increasing the number of parts and therefore the number of assembly steps.

[0049] Furthermore, as described above, the number of assembly steps is not increased, and the installation of the airfoil bearing is completed simply by pressing the airfoil bearing into the bearing installation hole 11 and slot 12 in the housing 10. This also has the effect of significantly speeding up the installation process of the airfoil bearing on the air compressor assembly line, thereby improving productivity.

[0050] As mentioned above, the present invention has been described with reference to the embodiments shown in the drawings, but these are merely examples, and those skilled in the art will understand that various modifications and other equivalent embodiments are possible. Therefore, the true technical scope of protection of the present invention should be determined by the following claims.

Claims

1. a foil assembly in which a bump foil and a top foil are overlapped in a cylindrical shape; a spacer attached to a bent portion formed to protrude radially from the foil assembly; The foil assembly and the folded portion are inserted into a bearing installation hole and a slot formed in the housing of the air compressor, and a circumferential gap is eliminated inside the slot by the spacer; a receiving portion into which the locking piece of the spacer is inserted is formed on both wall bodies on the entrance side of the slot, and a locking protrusion is formed on an end of the receiving portion on the entrance side of the slot, with which the end of the locking piece is locked; the spacer includes side plate portions and connecting portions connecting rear ends of the side plate portions, and the front portions of the side plate portions are cut in the length direction, and portions above the cut lines are bent outward on both sides to form the locking pieces.

2. 2. The airfoil bearing installation structure according to claim 1, wherein the locking piece has elasticity that allows it to be deformed and restored inward and outward directions of the spacer.

3. 2. The airfoil bearing installation structure according to claim 1, wherein a plurality of fastening holes are formed in the bent portion of the foil assembly, an equal number of fastening holes are formed in both side plate portions of the spacer, and fastening members are installed through the fastening holes to fix the spacer to the bent portion.

4. 4. The airfoil bearing installation structure of claim 3, wherein the fastening member includes: a base that is in close contact with one side of the spacer; extensions that are horizontally bent and extended from both sides of an upper end of the base, the extensions passing through the bent portions and the fastening holes of the spacer; and locking portions that are bent downward from ends of the extensions and in close contact with the other side of the spacer.

5. 2. The installation structure of an airfoil bearing according to claim 1, wherein the spacer has an open front end so that it can be axially sandwiched outside the bent portion of the foil assembly.

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