KR102252923B1 - Air foil radial bearing and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an airfoil radial bearing capable of supporting a load acting in an axis-orthogonal direction of a rotary shaft, and a manufacturing method thereof. The airfoil radial bearing (100) of the present invention includes: a bearing housing (110) having a through hole (111) into which a rotary shaft is inserted; a cylindrical top foil (120) inserted into the through hole, having a diameter smaller than the through hole, and including a slit-type opening part (121) formed on the outer circumference surface in an insertion direction of the rotary shaft; a bump foil assembly (140) including one single thin sheet (141) surrounding an outer surface of the top foil, and a plurality of bump foils (142) attached to an inner surface of the thin sheet to be located between the top foil and the thin sheet; an inward protrusion (112) formed in one end part of the through hole of the bearing housing to support an end part of the bump foil assembly and the top foil; a groove part (122) formed on the outer circumference surface of the top foil in an insertion direction of the rotary shaft; a pin member (130) bonded to the groove part; and a pin member coupling groove (113) formed on an inner surface of the through hole of the bearing housing.

Description

Air foil radial bearing and manufacturing method thereof TECHNICAL FIELD

The present invention relates to an airfoil radial bearing supporting a load acting in a direction perpendicular to the axis of a rotation shaft, and a manufacturing method thereof.

This technology is applied to turbomachines with airfoil bearings such as turbo compressors, turbo blowers, turbo chillers, and turbo generators.

The airfoil bearing is divided into an airfoil thrust bearing supporting an axial load and an airfoil radial bearing supporting a load in a perpendicular direction of the axis.

Among these, the airfoil radial bearing is composed of a bearing housing, a top foil inserted into the bearing housing, and a wavy bump foil supporting the top foil, and uses a hydrodynamic pressure formed between the top foil and the rotating shaft. It operates in a load-bearing manner.

That is, as the rotating shaft coupled to the bearing housing rotates at a high speed, a dynamic pressure between the top foil and the rotating shaft is formed, and by this dynamic pressure, the bump foil and the top foil are pressurized and deformed to form an air film between the rotating shaft and the top foil. As a result, friction due to high-speed rotation of the rotating shaft is reduced.

1 is a view showing an example of a conventional airfoil radial bearing. As shown, a conventional airfoil radial bearing includes a bearing housing 10 and a bump foil 20 inserted into the bearing housing 10. And a top foil 30 fitted into the inside of the bump foil 20, a bump sheet 50 positioned between the bump foil 20 and the top foil 30, and fastened to the bearing housing 10. It consists of a bearing cap (40).

In addition, the top foil 30 has a top foil protrusion 32 formed toward the bearing housing 10 and the bearing cap 40 side, and the bearing housing 10 has a top foil protrusion 32 on one side thereof. A coupling groove (not shown) to be fitted and coupled is formed, and a fixing groove 41 to which the other side top foil protrusion 32 is fitted and coupled is formed in the bearing cap 40.

In spite of increasing the thickness of the top foil 30, such conventional airfoil radial bearings do not perform bending and welding work of the top foil 30, so that precision can be maintained and rotated at high speed and high load. Although the effect can be expected to some extent in that the generated vibration is minimized and the reliability of the product is improved, a bearing cap 40 that fixes the top foil 30 so that it does not flow inside the bearing housing 10 is essential. Since it is provided, there is a problem in that the structure is complex and the manufacturing cost is also greatly increased.

In addition, in the conventional airfoil radial bearing, the bump foil 20, the bump sheet 50, and the top foil 30 must be sequentially inserted into the bearing housing 10, and the bump foil 20 and the top foil 30 The bump foil 20 and the ends 22 and 51 of the bump seat 50 are bent, respectively, so that) does not flow in the bearing housing 10, and the bump foil 20 and the top cloth are included in the bearing housing 10. Since the fine bump foil coupling groove 12 must be formed so that the bent ends 22 and 51 of the work 30 can be inserted, the assembling property and fabrication are very poor.

Particularly, considering that the bump foil 20 is not formed integrally and follows a configuration divided into several pieces for effective shock absorption, the assembling property becomes worse and a plurality of bump foil coupling grooves in the bearing housing 10 Since (12) must be formed, the fabrication property is also poorer.

Korean Patent Publication No. 10-1632356

The present invention has been conceived to solve the above problems, and an object of the present invention is to provide an airfoil radial bearing and a method of manufacturing the same, which is easy to assemble and manufacture a bump foil and a top foil without requiring a bearing cap.

In order to achieve the above object, the airfoil radial bearing of the present invention includes a bearing housing having a through hole into which a rotation shaft is inserted, and is inserted into the through hole and has a diameter smaller than that of the through hole, and is formed along the insertion direction of the rotation shaft on an outer circumferential surface. A cylindrical top foil having a slit-shaped opening, a single sheet covering the outer surface of the top foil, and a plurality of bump foils attached to the inner surface of the thin sheet so as to be positioned between the top foil and the sheet. A bump foil assembly, an inward step formed at one end of the through hole of the bearing housing to support an end of the top foil and bump foil assembly, a groove formed in the outer peripheral surface of the top foil in the insertion direction of the rotation shaft, and the groove portion And a pin member attached through bonding, and a pin member coupling groove formed on an inner surface of the through hole of the bearing housing.

In addition, the bump foil includes a single attachment surface attached to the thin plate sheet and a plurality of foil portions extending from the attachment surface in the rotational direction of the rotation axis, and the foil portions are spaced apart from each other in the direction of insertion of the rotation axis. Can be formed.

In this case, the foil portion is formed such that a flat portion in contact with the thin plate sheet and a round portion in close contact with the top foil are repeatedly formed, and the curvatures of adjacent round portions may be configured differently.

In addition, the present invention includes a bearing housing having a through hole into which a rotation shaft is inserted, and a cylindrical top foil that is inserted into the through hole and has a diameter smaller than the through hole and has a slit-shaped opening formed along the insertion direction of the rotation shaft on an outer circumferential surface thereof. , A single sheet covering the outer surface of the top foil, and a bump foil assembly including a plurality of bump foils attached to the inner surface of the thin sheet to be positioned between the top foil and the sheet, and the top foil and bump foil assembly An inward step formed at the end of the bearing housing to support one end of the top foil, a groove formed in the direction of insertion of the rotation shaft on the outer circumferential surface of the top foil, a pin member coupled to the groove, and formed on the inner surface of the bearing housing In the method of manufacturing an airfoil radial bearing including a pin member coupling groove, the bump foil assembly is formed to repeat a flat portion in contact with the thin plate sheet and a round portion in close contact with the top foil on a metal plate to produce a bump foil original plate. And forming a single attachment surface attached to the thin plate sheet and a plurality of foil portions extending from the attachment surface by discharge-processing the bump foil original plate, and cutting the bump foil original plate into a predetermined size to form a plurality of bump foils. It is manufactured by completing the steps of completing and, by spot welding the attachment surface of the bump foil to the inner surface of the thin sheet to attach the bump foils to the inner surface of the thin sheet at regular intervals.

In addition, the top foil includes the steps of preparing a cylindrical top foil body, forming a slit-shaped opening along the insertion direction of the rotation shaft through electric discharge processing on the outer circumferential surface of the top foil body, and discharging on the outer circumferential surface of the top foil body. Manufactured by forming a groove along the insertion direction of the rotation shaft through processing, applying a heat-resistant high-rigidity bond to at least one of the groove and the pin member, and bonding the pin member to the groove part. Can be.

In the present invention configured as described above, a groove is formed on the outer circumferential surface of the top foil in the direction of insertion of the rotating shaft, a pin member is attached to the groove through bonding, and a pin member coupling groove is formed on the inner surface of the through hole of the bearing housing. Therefore, unlike the prior art, the bearing cap is not required, so the structure is simple and the fabrication is easy.

In addition, in the present invention, since the groove portion of the top foil is formed through discharge processing and the pin member is attached through bonding, there is no thermal deformation during the manufacturing process, so that an even air film can be formed between the top foil and the rotating shaft when rotating the rotating shaft. As a result, vibration is not generated, and product reliability is greatly improved.

In addition, the present invention has a bump foil assembly in which a bump foil and a thin sheet are integrated, so that assembly is facilitated, and when a bump foil and a sheet of sheet are combined, only one spot welding is allowed, so that the thermal deformation caused by welding can be minimized. There is an effect that can be.

In addition, according to the present invention, when the curvature of adjacent round portions formed on the bump foil is formed differently, since the inherent impact energy absorbed by each round portion is different, there is an effect that more effective shock absorption is possible.

1 is an exploded perspective view of a conventional airfoil radial bearing.
Figure 2 is an exploded perspective view of the airfoil radial bearing according to the present invention.
3 is a front view of an airfoil radial bearing according to the present invention.
Figure 4 is a perspective view of the main part of the bump foil assembly constituting the present invention.
5 is a view showing the assembly process of the airfoil radial bearing according to the present invention.

Features and advantages of the present invention will become more apparent from the detailed description of the following preferred embodiments based on the accompanying drawings.

Prior to this, terms or words used in the present specification and claims are based on the principle that the inventor can appropriately define the concept of the term in order to describe his or her invention in the best way. It must be interpreted as a corresponding meaning and concept.

In addition, terms or words used in the specification and claims are used only to describe specific embodiments, and are not intended to limit the present invention.

For example, a singular expression includes a plural expression unless the context clearly indicates otherwise. In addition, terms such as "comprises" or "includes" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more It is to be understood that other features or possibilities of the presence or addition of numbers, steps, actions, components, parts, or combinations thereof are not preliminarily excluded.

In addition, when a part such as a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the case where the other part is "directly above", but also the case where there is another part in the middle. Conversely, when a part such as a layer, film, region, plate, etc. is said to be "under" another part, this includes not only the case where the other part is "directly below", but also the case where there is another part in the middle.

In addition, terms including ordinal numbers such as "first" and "second" used in the present specification may be used to describe various elements, but the elements are not limited by the terms, and the terms are It is used only for the purpose of distinguishing one component from other components.

Hereinafter, in describing an embodiment of the present invention in detail with reference to the drawings, the same reference numerals are used for the same configuration, and only different parts will be mainly described so as not to overlap as possible for clarity.

Figure 2 is an exploded perspective view of the airfoil radial bearing according to the present invention, Figure 3 is a front view of the airfoil radial bearing according to the present invention, Figure 4 is a perspective view of the main part of the bump foil assembly constituting the present invention, shown As described above, the airfoil radial bearing 100 of the present invention includes a bearing housing 110, a top foil 120 inserted into the bearing housing 110, and a bump foil assembly 140.

The bearing housing 110 has a through hole 111 into which a rotation shaft is inserted, and an inward stepped step 112 is formed at one end of the through hole 111.

The top foil 120 is a cylindrical metal member having a diameter smaller than the through hole 111 of the bearing housing 110, and is inserted into the through hole 111 of the bearing housing 110 to be inserted into the inward stepped step 112 One end is supported by ).

On the outer circumferential surface of the top foil 120, a slit-shaped opening 121 is formed along the insertion direction of the rotation shaft to prevent deformation due to thermal expansion and contraction.

In addition, a groove 122 is formed on the outer surface of the top foil 120 in the insertion direction of the rotation shaft.

In addition, a pin member 130 is coupled to the groove portion 122 through bonding.

The reason why the pin member 130 is coupled to the groove portion 122 through bonding is because when welding is performed, the smoothness of the inner and outer surfaces of the top foil 120 becomes poor as the periphery of the groove portion 122 is thermally deformed. to be.

In this case, as a uniform air film cannot be formed between the top foil 120 and the rotating shaft, the top foil 120 cannot normally support the load of the rotating shaft, and this causes a lot of noise and vibration when rotating at high speed. The life of the bearing is drastically reduced.

Meanwhile, a pin member coupling groove 113 into which the pin member 130 is fitted is formed on an inner surface of the through hole 111 of the bearing housing 110. The pin member coupling groove 113 is formed along the inner surface of the through hole 111 in the insertion direction of the rotation shaft.

Therefore, since the top foil 120 is inserted into the through hole 111 while the pin member 130 is inserted into the pin member coupling groove 113, it is possible to maintain a stable posture without rotating along a rotating shaft rotating at a high speed. do.

The bump foil assembly 140 is inserted into the through hole 111 of the bearing housing 110 together with the top foil 120 while surrounding the outer circumferential surface of the top foil 120, and the top foil 120 and the through hole It is located between (111) and protects the top foil 120 by absorbing frictional shock and frictional heat generated from the top foil 120 when the rotating shaft starts or stops rotating.

Such a bump foil assembly 140 includes a single thin plate sheet 141 surrounding the outer surface of the top foil 120 and the thin plate sheet 141 so as to be positioned between the top foil 120 and the thin plate sheet 141. ) Is composed of a plurality of bump foils 142 attached to the inner surface of the.

In this case, the bump foils 142 have a single attachment surface 142a attached to the thin plate sheet 141, and a plurality of foil portions 142b extending from the attachment surface 142a in the rotational direction of the rotation axis. can do. The foil portions 142b are formed to be elongated along the rotational direction of the rotational shaft, and are formed at regular intervals with each other along the insertion direction of the rotational shaft.

Meanwhile, the foil portion 142b is formed so that the contact portion 142c in contact with the thin plate sheet 141 and the round portion 142d in close contact with the top foil 120 are repeatedly formed.

In this case, it is preferable to form different curvatures of the adjacent round portions 142d.

When the curvatures of the round portions 142d are formed differently as described above, since the inherent impact energy absorbed by each round portion 142d is different, more effective shock absorption becomes possible.

The bump foil assembly 140 configured as described above is manufactured by the following method.

First, a bump foil original plate having a wave pattern is formed so that the contact portion 142c in contact with the thin plate sheet 141 and the round portion 142d in close contact with the top foil 120 are repeatedly formed on a metal plate having a predetermined length and width. Make it.

Then, the bump foil original plate is discharged to form a single attachment surface 142a attached to the thin plate sheet 141 and a plurality of foil portions 142b extending from the attachment surface 142a.

Then, the bump foil original plate is cut to a predetermined size through electric discharge processing to complete a plurality of bump foils 142.

Electric discharge machining is a method of transferring and processing the shape of the same cross-section as the machining electrode to the work by intermittently discharging between the machining electrode and the work piece in an insulating working liquid such as kerosene. Because of this, it is widely used for special processing.

Therefore, since the foil part 142b is manufactured using electric discharge processing, precise manufacturing without thermal deformation is possible.

In addition, by spot welding (S) the attachment surface (142a) of the bump foil 142 to the inner surface of the thin plate sheet 141 and attaching the bump foil 142 to the inner surface of the thin plate sheet 141 at regular intervals, the bump The foil assembly 140 is completed.

As described above, since the bump foil assembly 140 of the present invention allows spot welding (S) only in one place of the attachment surface 142a, thermal deformation due to welding can be minimized.

Meanwhile, the top foil 120 is manufactured by the following method.

First, a cylindrical top foil body is prepared.

In addition, a slit-shaped opening 121 is formed on the outer peripheral surface of the top foil body along the insertion direction of the rotation shaft through discharge processing.

In addition, a groove 122 is formed on the outer peripheral surface of the top foil body along the insertion direction of the rotation shaft through discharge processing.

And, after applying a heat-resistant (300°C) high-stiffness bond capable of withstanding a high friction temperature generated when rotating the rotating shaft on at least one side of the groove portion 122 and the pin member 130, the groove portion 122 When the pin member 130 is inserted and bonded, the top foil 120 is completed.

Since the top foil 120 is manufactured only through electric discharge processing and bonding, it can be precisely manufactured without thermal deformation due to welding.

5 is a view showing the assembly process of the airfoil radial bearing according to the present invention, as shown, the airfoil radial bearing 100 of the present invention manufactured by the above method is a top foil 120 After matching the pin member 130 to the pin member coupling groove 113 while the bump foil assembly 140 is wound on the outside, the above-mentioned until one end is in close contact with the inward stepped step 112 of the bearing housing 110. Assembly is very easily completed by simply inserting the top foil 120 into the through hole 111 of the bearing housing 110.

The top foil 120 assembled in this way is in a state in which the pin member 130 is fitted and coupled to the pin member coupling groove 113, so it does not rotate along the rotation axis and maintains a stable posture, and there is no thermal deformation due to welding. Since it is manufactured with precision, vibration is not generated while an even air film is formed between the top foil 120 and the rotating shaft when rotating the rotating shaft.

Therefore, the product reliability of the airfoil radial bearing of the present invention is very high.

As described above, preferred embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above-described embodiments, and those of ordinary skill in the art to which the present invention pertains are modified without departing from the spirit of the present invention. It is possible, and such modifications will fall within the scope of the present invention.

100... airfoil radial bearings
110...bearing housing 111...through hole
112...Inward stepped step 113...Pin member coupling groove
120...top foil 121...open
122...groove part 130...pin member
140...Bump foil assembly 141...Sheet sheet
142...bump foil 142a...attachment surface
142b...foil part 142c...contact part
142d...round part

Claims (5)

delete A bearing housing 110 having a through hole 111 into which a rotation shaft is inserted, and a slit shape that is inserted into the through hole 111 and has a diameter smaller than that of the through hole 111 and is formed along the insertion direction of the rotation shaft on the outer circumferential surface. Between the cylindrical top foil 120 having an opening portion 121 of, and a single thin plate sheet 141 surrounding the outer surface of the top foil 120 and the top foil 120 and the thin plate sheet 141 Supports the bump foil assembly 140 having a plurality of bump foils 142 attached to the inner surface of the thin plate sheet 141 to be positioned at, and the end of the top foil 120 and the bump foil assembly 140 An inward stepped step 112 formed at one end of the bearing housing 110, a groove 122 formed in an insertion direction of a rotation shaft on an outer circumferential surface of the top foil 120, and a pin coupled to the groove 122 In the method of manufacturing an airfoil radial bearing including a member 130 and a pin member coupling groove 113 formed on an inner surface of the bearing housing 110,
The bump foil assembly 140 is a step of forming a bump foil original plate by repeatedly forming a contact portion 142C in contact with the thin plate sheet 141 and a round portion 142d in close contact with the top foil 120 on a metal plate;
Forming a single attachment surface (142a) attached to the thin plate sheet 141 and a plurality of foil portions (142b) extending from the attachment surface (142a) in the rotational direction of the rotation axis by electric discharge processing the bump foil original plate;
Cutting the bump foil original plate into a predetermined size to complete a plurality of bump foils (142);
Spot welding the attachment surface 142a of the bump foil 142 to the inner surface of the thin sheet 141 to attach the bump foils 142 to the inner surface of the thin sheet 141 at regular intervals,
The top foil 120 is
Preparing a cylindrical top foil original body;
Forming a slit-shaped opening 121 along the insertion direction of the rotating shaft through electric discharge processing on the outer circumferential surface of the original top foil;
Forming a groove 122 along the insertion direction of the rotation shaft through electric discharge processing on the outer circumferential surface of the original top foil;
Applying a heat-resistant high-rigidity bond to at least one side of the groove portion 122 and the pin member 130;
Including the step of inserting and bonding the pin member 130 to the groove portion 122,
The foil portions 142b are formed with a predetermined interval therebetween in the insertion direction of the rotation shaft,
The foil portion 142b is formed such that a contact portion 142c in contact with the thin plate sheet 141 and a round portion 142d in close contact with the top foil 120 are repeatedly formed;
The curvatures of the adjacent round portions 142d are different.
Airfoil radial bearing manufacturing method, characterized in that. delete delete delete

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