KR101204867B1 - Air foil bearing - Google Patents

Abstract

The present invention relates to an air foil bearing having a configuration in which the oil film is kept uniform and usable in various operating environments.

Air foil bearing according to the present invention is a first plate; A second plate facing the first plate; At least one elastic member arranged between the first plate and the second plate; A top foil disposed circumferentially on an outer side of the second plate; And a plurality of support members arranged between the second plate and the top foil to support the top foil and have different heights.

Air foil bearing

Description

Air foil bearing

1 is a plan view showing the structure of a conventional air foil bearing.

FIG. 2 is a side view illustrating a structure of a bump foil of the air foil bearing of FIG. 1. FIG.

3 is a plan view showing the structure of an air foil bearing according to an embodiment of the present invention.

4 is a side view showing the structure of the air foil bearing of FIG.

5 is a side view showing the structure of an air foil bearing according to another embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: air foil bearing 110: first plate

120: second plate 130: elastic member

140: coupling member 150: support member

160: top foil

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to air foil bearings, and more particularly, to air foil bearings having a configuration in which an oil film is kept uniform and usable in various operating environments.

Typically an air foil bearing can be applied to support the rotor in an axial or radial direction. The air foil bearing is not a method of supporting the shaft by using an oil film as in the conventional ball bearings or journal bearings, but is a bearing supporting the shaft by forming a high-pressure air layer between the air foil and the shaft.

Air foil bearings are particularly effective for supporting rotating bodies that rotate at high speeds. For example, the air foil bearing may be applied to a turbo compressor or the like of a gas turbine engine. Since gas turbine engines require compressed air to burn fuel, a turbo compressor for compressing air is provided. The compressed air in the turbo compressor is mainly used for combustion of fuel, but some compressed air can be supplied to the air foil bearing, so that the impeller shaft of the turbo compressor or the rotating shaft of the gas turbine engine can be supported by the air foil bearing.

 1 is a plan view illustrating a structure of a conventional air foil bearing, and FIG. 2 is a side view illustrating a structure of a bump foil of the air foil bearing of FIG. 1.

Referring to FIG. 1, the conventional air foil bearing 1 has a base plate 10 in which the coupling member 20 is welded at predetermined intervals in the circumferential direction, and one end thereof is fixed to the coupling member 20 by welding. Top foil 40 is included. In addition, the air foil bearing 1 is provided with a bump foil 30 welded to the base plate 10 to support the top foil 40.

The bump foil 30 is formed in the shape of a wave as shown in FIG. 2. Here, the bump foil 30 is formed such that the height of the floor (highest part of the wave) increases as the distance from the coupling member 20 increases. In other words, as seen in FIG. 2, the height of the floor of the left wave is the lowest, and the height of the floor of the wave increases toward the right. For example, the height of the leftmost wave floor may be 0.55 mm, the height of the next wave floor is 0.60 mm, and the height of subsequent waves is 0.65 mm.

As the bump foil 30 is installed as described above, friction is generated by sliding contact between the top foil 40 and the bump foil 30 during the operation of the rotating body. According to the related art, each top foil 40 is It is configured to be supported by the bump foil 30 formed of the leaf spring.

However, the following problems exist in the conventional air foil bearing 1 as described above.

First, in the conventional air foil bearing 1, the bump foil itself is formed of a leaf spring as shown in FIGS. 1 and 2. However, fatigue failure of the leaf spring may occur due to repeated external force applied to the leaf spring during prolonged use.

In addition, even if the leaf spring does not reach fatigue failure, if the load is concentrated on a specific foil of the bearing, and deformation occurs in the portion where the load is concentrated, the bearing performance of the bearing is reduced, thereby causing the rotating body to contact the foil. There is a problem that the whole and the bearing can be broken.

In addition, there is a problem in that the air oil film is reduced by the concentrated load, and thus excessive heat is generated to reduce cooling efficiency.

In addition, there has been a problem that it is not easy to manufacture a leaf spring having a mechanical property suitable for the use of the product and the use environment.

An object of the present invention is to provide an air foil bearing in which the oil film is uniformly maintained, usable in various operating environments, and the bearing is stably supported to improve durability and operational reliability.

Air foil bearing according to the present invention is a first plate; A second plate facing the first plate; At least one elastic member arranged between the first plate and the second plate; A top foil disposed circumferentially on an outer side of the second plate; And a plurality of support members arranged between the second plate and the top foil to support the top foil and have different heights.

By providing such a structure, since an oil film is kept uniform, the durability and operational reliability of a product can improve, and the effect which can be used in various operating environments can be acquired. In the present invention, the elastic member may include a coil spring.

In the present invention, the elastic member may include a coil spring.

In the present invention, the elastic member may include a leaf spring.

In the present invention, the height of the plurality of support members may be sequentially increased from one side to the other side.

An air foil bearing according to another aspect of the present invention includes a first plate and a second plate facing each other; A coil spring arranged between the first plate and the second plate; A coupling member arranged in the circumferential direction on the second plate; A top foil coupled to one side of the coupling member; And a plurality of rigid bodies arranged between the second plate and the top foil to support the top foil and have different heights.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The spirit of the present invention is not limited to these embodiments, and other embodiments that can be easily suggested by those skilled in the art who understand the spirit of the present invention within the scope of the same idea can be easily suggested by addition, deletion, addition and modification of the components. Examples will also be included in the spirit of the invention.

3 is a plan view illustrating a structure of an air foil bearing according to an exemplary embodiment of the present invention, and FIG. 4 is a side view illustrating a structure of an air foil bearing of FIG. 3.

The air foil bearing 100 of the embodiment illustrated in FIGS. 3 and 4 includes a first plate 110, a second plate 120, an elastic member 130, a top foil 160, and a support member ( 150).

The first plate 110 and the second plate 120 are disposed in directions substantially parallel to each other. The elastic member 130 is interposed between the first plate 110 and the second plate 120 to provide a predetermined elastic force. The top foil 160 has one side fixed to the upper portion of the second plate 120 and is disposed in the circumferential direction. The plurality of support members 150 are formed between the second plate 120 and the top foil 160 to support a fixed position of the top foil 160. A plurality of coupling members 140 may be further included on the second plate 120 to be spaced apart from each other in the circumferential direction so that the top foil 160 and the second plate 120 are coupled to each other.

The first plate 110 and the second plate 120 are formed in directions substantially parallel to each other. Here, the first plate 110 and the second plate 120 may be formed of the same material, shape and size.

At least one elastic member 130 is formed between the first plate 110 and the second plate 120. The elastic member 130 is interposed between the first plate 110 and the second plate 120 to provide a predetermined elastic force to the first plate 110 and the second plate 120. In addition, one end of the elastic member 130 is coupled to the first plate 110, the other end is coupled to the second plate 120, so that the first plate 110 and the second plate 120 is coupled to. Can be performed.

The elastic member 130 may be formed of a coiled spring as shown in FIG. 4. Here, the coil spring 130 is a spring made by winding the iron rod in a spiral shape, and coil springs having various mechanical properties are already commercialized. Therefore, it is possible to have an effect that can be easily selected / procured among the coil springs produced before, without separately manufacturing an elastic member suitable for the specifications of the product.

On the other hand, a plurality of coil springs may be formed in the circumferential direction. Although four coil springs are formed per one top foil 160 in FIG. 4, the spirit of the present invention is not limited thereto, and various shapes and characteristics may be determined according to the mechanical characteristics and the use environment of the air foil bearing 100. It will be appreciated that a number of coil springs are applicable.

In addition, the pair of coil springs 130 may be formed to have all the same mechanical properties (for example, elastic modulus, size, shape, etc.), and each coil spring 130 may have different mechanical properties. It may be formed to have.

As such, as the coil spring is used as the elastic member 130 of the air foil bearing 100, the manufacturing cost of the product may be reduced and the manufacturing process may be simplified. In addition, by using a coil spring having a variety of mechanical properties, it is possible to obtain an effect that can easily manufacture the air foil bearing 100 suitable for various operating environments. In addition, since the coil spring having excellent durability as compared to the conventional leaf spring is used as the elastic member, it is possible to prevent the fatigue fracture of the spring, and furthermore, the durability and the operation reliability can be obtained.

The coupling member 140 may be attached onto the second plate 120 by glue bonding or the like, and as shown in FIG. 3, the coupling member 140 may be welded in the radial direction of the second plate 120 to form the second plate 120. It may be fixed.

The top foil 160 is a thin metal plate to form an air film between the rotor and the air foil bearing 100. Each top foil 160 of the air foil bearing 100 according to the present invention is formed with a substantially rectangular planar friction portion, one end of the friction portion is coupled to the coupling member 140 by welding or the like to be fixed. do.

In addition, a coating layer (not shown) may be formed on the surfaces of the top foils 160 facing the rotors for smooth rotation of the rotors inserted into the top foils 160 disposed to overlap each other. In addition, since the top foils 160 are arranged to overlap each other in one direction, the rotating body is smoothly rotated in a specific direction, and the rotation is limited in the other direction.

One or more grooves (not shown) are formed in the friction portion, and the friction portion may be separated into two or more pieces in the circumferential direction by the groove. The number of pieces to be separated may be the same for each of the top foils 160, but if the number of pieces is different, friction damping between the rotor and the top foils 160 may be increased. In addition, the top foils 160 may be made of various materials, and Inconel, which is a rigid material that does not generate deformation even at a high temperature, may be used.

Meanwhile, a plurality of support members 150 are formed between the second plate 120 and the top foil 160 to support the top foil 160.

The present invention constituting such a configuration is characterized in that the elastic member 130 and the support member 150 perform the role that the conventional leaf spring performs. In other words, a bump foil (see 30 in FIG. 1) formed of a leaf spring has been conventionally formed between the base plate (see 10 in FIG. 1) and the top foil (see 40 in FIG. 1). In addition, the bump foil 30 serves to support the top foil 10 while providing an elastic force between the base plate 10 and the top foil 40. Accordingly, there has been a problem that the leaf spring may be fatigue failure or deformation may occur and the bearing may be broken by repeatedly applying external force to the leaf spring. In order to solve this problem, the air foil bearing 100 according to the present invention is configured to separate the elastic member 130 and the support member 150, and to use a coil spring as the elastic member 130. By such a structure, the durability and operational reliability of the air foil bearing can be improved, the manufacturing cost can be reduced, and the manufacturing process can be obtained.

On the other hand, the plurality of support members 150 may be formed so that the height increases as the distance from the coupling member 140. In other words, as seen in FIG. 4, the height of the support member 150 on the left side is the lowest, and the height of the support member 150 increases toward the right side. In addition, although four support members 150 are formed per one top foil 160 in FIG. 4, the spirit of the present invention is not limited thereto, and the mechanical characteristics and use of the air foil bearing 100 may be used. It will be obvious that the support members 150 of various shapes and numbers can be applied according to the environment.

Hereinafter, the operation of the air foil bearing configured as described above will be described.

Air foil bearing 100 according to the present invention can be installed in a variety of rotary machines, it is generally used for a rotary machine that rotates at high speed. Therefore, the rotor is inserted into the space formed inside the air foil bearing 100 to rotate.

When the rotor rotates slowly in one direction, the high pressure gas starts to flow into the space between the rotor and the top foil 160. The rotor is in contact with the top foil 160 until its rotational speed reaches a normal speed. When the gas pressure between the rotating body and the top foil 160 rises further due to the rotation of the rotating body, the rotating body floats from the top foil 160.

Here, when the rotary machine is operated, the air foil bearing 100 not only supports the weight of the rotating body, but also facilitates the rotation of the rotating body. And, when the rotating body is eccentric by vibration, etc., the air foil bearing 100 generates friction by sliding contact between the rotating body and the second plate 120 in order to absorb the vibration of the rotating body, It functions to damp the load.

In the air foil bearing 100 according to the present invention, the elastic member 130 and the support member 150 are separated from each other, and the phenomenon in which an external force acts directly on the elastic member 130 is prevented, thereby Breakage and deformation are prevented. In addition, by preventing damage and deformation of the elastic member 130 as described above, the durability and operation reliability of the product is improved and the manufacturing process is simplified.

On the other hand, in the case of the top foils 160, since the plurality of top foils 160 are arranged in an overlapping manner, friction damping is improved as a result of increased friction due to relative movement between the foils as compared to the integrated elastic foil.

By preventing the damage and deformation of the elastic member by the configuration of the present invention as described above, the durability and operational reliability of the product can be improved, and the effect of being usable in various operating environments can be obtained.

5 is a side view showing the structure of an air foil bearing according to another embodiment of the present invention. The elastic member of the embodiment shown in FIG. 5 is characterized in that a leaf spring is used as the elastic member 230 as compared to the embodiment shown in FIGS. 3 and 4.

In other words, the elastic member 230 of the embodiment shown in FIG. 5 may be formed of a leaf spring. The leaf spring is formed between the first plate 210 and the second plate 220, and a separate support member 250 is provided on the second plate 220. By such a configuration, it is possible to prevent a phenomenon in which an external force is directly applied to the leaf spring, thereby preventing the breakage of the bearing and extending the life of the product. Conventional air foil bearings have not been able to achieve this effect because the leaf springs simultaneously accommodate the role of elastic members and support members.

The leaf spring may be formed in plural in the circumferential direction. In FIG. 5, four leaf springs are formed per one top foil 260. However, the spirit of the present invention is not limited thereto, and various shapes and shapes may be determined depending on the mechanical characteristics and the use environment of the air foil bearing 200. Naturally, the number of leaf springs is applicable.

The pair of leaf springs 230 may be formed to have all the same mechanical properties (for example, elastic modulus, size, shape, etc.), and the leaf springs 230 may be formed to have different mechanical properties. May be

By such a structure, the effect that damage and deformation of an elastic member are prevented can be acquired.

The air foil bearing according to the present invention has the effect that the oil film is kept uniform and can be used in various operating environments, the bearing is stably supported, and durability and operational reliability are improved.

Claims (5)

First plate; A second plate facing the first plate; At least one elastic member arranged between the first plate and the second plate; A top foil disposed circumferentially on an outer side of the second plate; And And a plurality of support members arranged between the second plate and the top foil to support the top foil and have different heights. Air foil bearing, characterized in that the height of the plurality of support members are sequentially increased as the distance from the center of the second plate. Claim 2 has been abandoned due to the setting registration fee. The method of claim 1, And the elastic member is a coil spring. Claim 3 has been abandoned due to the setting registration fee. The method of claim 1, And the elastic member is a leaf spring. delete A first plate and a second plate facing each other; A coil spring arranged between the first plate and the second plate; A coupling member arranged in the circumferential direction on the second plate; A top foil coupled to one side of the coupling member; And And a plurality of support members arranged between the second plate and the top foil to support the top foil and have different heights. Air foil bearing, characterized in that the height of the plurality of support members are sequentially increased as the distance from the center of the second plate.

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