KR20080086264A - Damping system of air foil bearing - Google Patents

Abstract

A damping system for an air foil bearing is provided to improve the endurance and operation reliability of a product by preventing a bearing from colliding with a rotating member when an apparatus abnormally operates. A damping system for an air foil bearing comprises an air foil bearing(110) supporting a rotating member(130) that rotates at high speed, a housing(120) containing the air foil bearing, and a damping member(125) protruding toward the rotating member from one side of the interior of the housing. The damping member has a length smaller than the difference between a gap, which is formed between the housing and the rotating member, and the maximum axial displacement of the rotating member during a normal operation.

Description

Damping system of air foil bearing

1 is a perspective view showing a conventional air foil bearing.

2 is a partial cross-sectional view of a portion of a conventional air foil bearing system.

3 is a partial cross-sectional view showing the structure of an impact damping system of an air foil bearing according to one embodiment of the present invention.

4 is a partial cross-sectional view showing the structure of an impact damping system of an air foil bearing according to another embodiment of the present invention.

5 is a partial cross-sectional view showing the structure of an impact damping system of an air foil bearing according to still another embodiment of the present invention.

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

100, 200, 300: Shock damping system for air foil bearings

110, 210, 310: air foil bearing 120, 220, 320: housing

125, 225, 325: shock damping members 130, 230, 330: rotating body

The present invention relates to an impact damping system of an airfoil bearing, and more particularly, to an impact damping system of an airfoil bearing in which an impact generated during abnormal operation of a device by an impact damping member is reduced.

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 gas turbine engine, a turbo compressor, an air cooling machine (ACM), a turbo refrigerant compressor (TRC), and the like.

1 is a perspective view showing a conventional air foil bearing.

Referring to FIG. 1, the air foil bearing 10 includes a base plate 11 and at least one air foil 12 installed on an upper surface of the base plate 11.

Here, the through hole 13 is formed in the center portion of the base plate 11. In addition, the air foil 12 has a function of damping and supporting the thrust 40 when the thrust 40 is applied to the thrust face 12a of the air foil 12.

Here, the air foil 12 is composed of a thin sheet elastic member, and is divided into a fan shape having an inner circumference and an outer circumference.

The rotating shaft 31 of the rotating body 30 is inserted into the through hole 13 formed in the center of the air foil bearing 10 having such a configuration, and the disk surface 32a and the trust surface of the air foil 12 ( 12a) is formed to face each other.

2 is a partial cross-sectional view showing a portion of a conventional air foil bearing system, in which the center line indicates that the air foil bearing system is vertically symmetrical.

Referring to FIG. 2, a conventional air foil bearing system 1 includes an air foil bearing 10 and a housing 20 that supports and wraps the air foil bearing 10.

The rotating body 30 interposed in the space formed in the housing 20 has a rotating shaft 31 and a disk having a predetermined thickness along the circumferential direction of the rotating shaft 31 and having a diameter larger than the diameter of the rotating shaft 31. (32) is provided.

The air foil bearing 10 includes a base plate 11 and an air foil 12.

And, the air foil bearing 10 is installed one each on the left and right inner surface of the space in the housing 20. Accordingly, the left and right side surfaces of the disc 32 are opposed to the trust surface 12a of the air foil 12 on the left and right sides, respectively, so that two regions are formed around the disc 32.

In addition, the housing 20 has two supply passages 23 for supplying cooling air to the two regions, respectively, and the discharge passage 24 allows the air passing through the regions to be discharged. Is formed. Here, high pressure air is generally used as cooling air.

Referring to the operation of the air foil bearing system (1) having such a configuration as follows. In detail, the thrust 40 generated by the rotation of the rotor 30 is supported without contact between the disk surface 32a and the thrust surface 12a of the air foil 12. On the other hand, the high-pressure air passing through the regions is discharged through the discharge passage (24).

According to this prior art, there is no separate anti-shock or shock damping member between the air foil bearing 10 and the rotor 30, so that the air foil bearing 10 and the rotor 30 are directly It is configured to be able to be contacted.

However, such a conventional air foil bearing system 1 has the following problems.

First, when the thrust 40 is excessively generated by the rotation of the rotor 30, the air layer 26 between the thrust surface 12a and the disk surface 32a of the air foil 12 is the thrust 40. In this case, contact friction occurs between the thrust face 12a of the air foil 12 and the disc face 32a. In addition, the air foil 12 may be directly impacted by the thrust 40.

In addition, the air foil bearing 10 and the rotating body 30 are more likely to collide during abnormal operation such as starting or stopping of the device on which the air foil bearing system 1 is mounted.

Therefore, the air foil 12 may be abrasion and friction heat due to friction, it may be damaged by the impact, resulting in a weakening of the durability of the air foil bearing 10.

It is an object of the present invention to provide an impact damping system of an airfoil bearing in which direct collision between the bearing and the rotor is prevented during abnormal operation of the machine by the impact damping member between the airfoil bearing and the rotor.

An impact damping system of an air foil bearing according to the present invention comprises: an air foil bearing for supporting a rotating body rotating at high speed; A housing in which the air foil bearing is accommodated; And an impact damping member protruding from the inner side of the housing toward the rotation body.

By having such a configuration, collision between the bearing and the rotating body is prevented during abnormal operation of the device, thereby improving the durability and operation reliability of the product and extending the life of the product.

In the present invention, the length of the impact damping member may be formed to be smaller than the difference between the distance between the housing and the rotating body and the maximum displacement in the axial direction of the rotating body during steady state operation.

In the present invention, the impact damping member may be formed at a point where the vertical distance from the rotation axis of the rotating body is minimum.

In the present invention, the impact damping member may include a contact member in contact with the rotating body, and an elastic member disposed between the housing and the contact member.

In the present invention, the impact damping member may include a gas injection pipe in which gas is injected.

In the present invention, the impact damping member may include a ball to enable rolling friction between each other when the rotor and the impact damping member contact.

According to another aspect, an impact damping system of an air foil bearing of the present invention includes: an air foil bearing supporting a rotating body rotating at high speed; A housing having a bearing accommodation portion formed therein; And a cushioning member formed between the air foil bearing and the rotating body so as to cushion an impact generated when the rotor and the air foil bearing collide with each other.

By providing such a structure, the impact which arises at the time of a collision of a bearing and a rotating body is alleviated, and the effect of extending the life of a product can be acquired.

In the present invention, the buffer member may be formed to be spaced apart from the rotating body during the normal operation of the rotating body.

In the present invention, the shock absorbing member may be formed to prevent contact between the rotor and the air foil bearing during abnormal operation of the rotor.

In the present invention, the buffer member may be formed on the opening side of the bearing accommodation portion.

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 partial cross-sectional view showing the structure of an impact damping system of an air foil bearing according to the present invention.

The impact damping system 100 of the air foil bearing according to the embodiment shown in FIG. 3 includes an air foil bearing 110 and a housing 120.

The air foil bearing 110 includes a base plate 111, a support member (not shown), an air foil 112, and an elastic member (not shown). The air foil bearing 110 supports the rotating body 130 that rotates at a high speed.

Support members (not shown) are formed on the base plate 111 so as to be spaced apart by a predetermined interval in the circumferential direction. The air foil 112 has one end coupled to the support member (not shown) and is bent to a predetermined curvature. An elastic member (not shown) is interposed between the base plate 111 and the air foil 112 to provide a predetermined elastic force to the air foil 112.

The support member (not shown) may be attached on the base plate 111 by welding or glue bonding or the like. In addition, the support member (not shown) may perform a function of compensating for the height difference caused by the thickness of the material itself of the elastic member (not shown).

An elastic member (not shown) is formed to intervene between the base plate 111 and the air foil 112. Here, the elastic member (not shown) may be provided as an arcuate leaf spring whose ends are elastically supported by the base plate 111. Therefore, the elastic member (not shown) may perform a function of absorbing and cushioning the generated force by a supporting action when a force is generated from the rotating body.

The air foil 112 is a thin metal plate to form an air film between the rotor 130 and the air foil bearing 110. Here, the air foils 112 include a friction part that is a rectangular plane and a fixing part that is formed at one end of the friction part and is bent in a square shape. In addition, in order to prevent the entirety of the air foil 112 from being moved in the circumferential direction or the longitudinal direction of the base plate 111, the fixing part may be configured to be inserted and fixed in the slot.

In addition, a coating layer (not shown) may be provided on the surfaces of the air foils 112 facing the rotor 130 for smooth rotation of the rotor 130 inserted into the air foils 112 disposed to overlap each other. This can be formed. In addition, since the air foils 112 are disposed to overlap each other in one direction, the rotating body 130 is smoothly rotated in a specific direction, and the rotation is limited in the other direction.

In addition, the air foil 112 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.

The rotating body 130 interposed in the bearing accommodation portion 122 has a rotating shaft 131 and a disk 132 having a predetermined thickness along the circumferential direction of the rotating shaft 131 and having a diameter larger than the diameter of the rotating shaft 131. ).

The housing 120 is formed with a bearing accommodation portion 122 in which the air foil bearing 110 is accommodated. And, the air foil bearing 110 is installed one each on the left and right sides of the inner surface of the bearing accommodation portion 122 in the housing 120. Accordingly, the left and right side surfaces of the disc 132 are formed to face each other with the thrust surface 112a of the air foil 112 on the left and right sides, and the bearing accommodation portion 122 has two regions bordering the disc 132. Is formed.

The housing 120 has two supply passages 123 for supplying high pressure air to each of the two regions, and a discharge passage 124 is formed to allow the air passing through the regions to be discharged.

On the other hand, the housing 120 in which the air foil bearing 110 is accommodated, the impact damping member 125 to prevent the collision between the air foil bearing 110 and the rotating body 130 is formed to a predetermined degree.

In the conventional air foil bearing system (see FIGS. 1 and 2), there is no separate anti-shock or impact damping member between the air foil bearing and the rotating body. Therefore, it was possible for the air foil bearing and the rotor to directly contact or collide with each other. Thus, when the base plate of the air foil bearing or the disk of the air foil and the disk of the rotor directly collide with each other, the air foil bearing has frictional wear and Friction heat could occur. In addition, the bearing may be damaged by such an impact, and thus there is a problem of weakening the durability of the air foil bearing. In order to solve such a problem, the impact prevention system 100 of the air foil bearing according to the present invention includes a separate impact damping member 125 between the air foil bearing 110 and the rotor 130. By such a configuration, it is possible to prevent the damage of the bearing due to the collision of the air foil bearing and the rotating body during abnormal operation of the device, to improve the durability of the product, and to improve the operation reliability.

The shock damping member 125 provided in the shock damping system 100 of the air foil bearing according to the present invention may include a contact member 125a and an elastic member 125b. In other words, one side of the elastic member 125b may be coupled to the recess 126 formed on one side of the housing 120, and the contact member 125a may be coupled to the other side of the elastic member 125b.

Therefore, even if a situation occurs in which the device is abnormally operated and the air foil bearing 110 and the rotating body 130 may collide, the rotating body is already before the air foil bearing 110 and the rotating body 130 directly collide with each other. The impact of the 130 on the impact damping member 125 and the air foil bearing 110 is reduced. Moreover, the impact and heat generated on the air foil bearing 110 by the elastic member 125b that provides a predetermined elastic force in the outward direction of the housing 120 may be further reduced.

Here, the contact member 125a may be formed of a material having a predetermined elastic force, for example, synthetic resin or rubber. The impact generated when the air foil bearing 110 and the rotating body 130 rotate by the contact member 125a having an elastic force may be further reduced.

In addition, although the contact member 125a is illustrated in a cylindrical shape having a rounded end in FIG. 3, the spirit of the present invention is not limited thereto, and the shape of the end of the contact member 125 may include a bearing 110 and a rotating body 130. It can be formed in a variety of structures that can reduce the impact generated when the collision of).

In addition, although the elastic member 125b is illustrated as a coil spring in FIG. 3, in addition to the coil spring, an elastic member having various shapes and materials, such as a leaf spring and a dish spring, may be applied.

On the other hand, the length B of the impact damping member 125 protruding from the housing 120 is the distance A between the housing 120 and the disk 132 and the maximum displacement in the axial direction at the time of steady state operation ( It may be formed smaller than the difference value (A-C) of C). For example, if the distance A between the housing 120 and the disk 132 is 150 µm and the maximum axial displacement C in the steady state operation is 80 µm, the length of the shock damping member 125 is It can be formed smaller than the 70㎛ difference between A and C. If the length of the shock damping member 125 is greater than the difference between A and C, the shock damping member 125 and the disk 132 are in constant contact with each other even during steady state operation, and abrasion occurs and the disk ( 132) can be damaged / broken.

As illustrated in FIG. 3, the impact damping member 125 formed in the housing 120 may be formed at a point where the vertical distance from the rotation shaft 131 of the rotor 130 is minimized. The shock damping member 125 may be formed at any position on one side of the bearing accommodation portion 122. However, since the linear velocity (v) of the object is determined by (radius (r) * angular velocity (ω)), the radius r decreases as the vertical distance from the rotation axis to the impact damping member 125 decreases. Accordingly, the linear velocity of the object is also reduced. Therefore, in order to minimize the impact generated when the impact damping member 125 and the disk 132 collide, the shock damping member 125 is the lowest end of the bearing receiving portion 122, that is, as shown in FIG. It may be formed on the opening side of the accommodation portion (122).

Hereinafter, the operation of the impact damping system 100 of the air foil bearing configured as described above will be described.

The impact damping system 100 of the air foil bearing according to the present invention may be installed in various rotary machines, but is generally used in rotary machines that rotate at high speed. Therefore, the rotor 130 is inserted into the hollow formed inside the air foil bearing 110 to rotate.

When the rotating body 130 rotates slowly in one direction, the high pressure gas starts to flow into the space portion between the rotating body 130 and the air foil 112. The rotor 130 is in contact with the air foil 112 until its rotational speed reaches a normal speed. Here, since the air foil 112 is supported by a bump foil (not shown) having a relatively high stiffness, the overall stiffness of the impact damping system 100 of the air foil bearing is increased. Directional displacement can be reduced and load bearing forces can also be increased.

When the gas pressure between the rotor 130 and the air foil 112 is further increased due to the rotation of the rotor 130, the rotor 130 is floated from the air foil 112. Here, when the rotary device is operated, the air foil bearing 110 not only supports the weight of the rotating body 130, but also helps to smoothly rotate the rotating body 130.

In particular, in the impact damping system 100 of the air foil bearing according to the present invention, the shock damping member 125 is provided between the air foil bearing 110 and the rotating body 130. Therefore, the phenomenon in which the air foil bearing 110 and the rotor 130 directly collide with each other is prevented due to an increase in axial displacement during abnormal operation such as starting or stopping of the device. That is, when the impact damping member 125 protrudes from the air foil bearing 110 toward the disk 132 of the rotating body 130 to a certain degree, and the rotating body 130 axially moves for a predetermined degree or more, the disk ( 132 attenuates the impact.

By the configuration of the present invention as described above, the safety of the device is installed, the rotating shaft is improved, the impact and heat is reduced to improve the durability and operation reliability of the product, the life of the product can be extended.

4 is a partial cross-sectional view showing the structure of an impact damping system of an air foil bearing according to another embodiment of the present invention. The impact damping member of the embodiment shown in FIG. 4 is characterized in that the impact generated when the impact damping member collides with the disk is further reduced by the injection of high pressure gas from the shock damping member.

The impact damping member 225 of the impact damping system 200 of the air foil bearing shown in FIG. 4 includes a protrusion 225a and a gas injection tube 225b. The protrusion 225a is formed at one side of the housing 220. The gas injection pipe 225b is accommodated in the protrusion 225a to inject a predetermined gas when the air foil bearing 210 collides with the rotor 230. In other words, a gas injection pipe 225b for injecting a high pressure gas is formed inside the protrusion 225a formed at one side of the housing 220, so that the air foil bearing 210 collides with the rotor 230. Shock injection is performed using the injected gas.

Here, the protrusion 225a may be formed of a material having a predetermined elastic force, for example, synthetic resin or rubber. The impact generated when the air foil bearing 210 and the rotating body 230 rotate by the protrusion 225a having such an elastic force may be further reduced.

Here, the gas injection pipe 225b may be formed to inject low pressure high pressure gas. By the low temperature and high pressure gas, the heat that may occur during the high speed rotation of the rotor 230 may be cooled.

According to another embodiment of the present invention as described above it is possible to obtain the effect of improving the safety of the device is installed a rotating shaft. In addition, the impact and heat generation is reduced by the injected high-pressure gas to improve the durability and operation reliability of the product, it is possible to obtain the effect of extending the life of the product.

5 is a partial cross-sectional view showing the structure of an impact damping system of an air foil bearing according to still another embodiment of the present invention. Compared to the embodiment shown in FIG. 3, the impact damping member of the embodiment illustrated in FIG. 5 is characterized in that the impact damping member 325 is configured by using rolling friction by the ball.

The impact damping member 225 of the shock damping system 200 of the air foil bearing shown in FIG. 4 includes a ball 325a, a lubricating member 325b, a coupling member 325c, and a ball housing 325d. do.

The ball housing 325d is disposed on one side of the housing 320. The ball 325a is disposed in the ball housing 325d. The coupling member 325c couples the ball housing 325d and the housing 320. The lubrication member 325b allows the ball 325a to rotate smoothly. In other words, a ball 325a is formed at one side of the housing 320, and when the air foil bearing 310 collides with the rotor 330, the rolling friction between the rotatable ball 325a and the disk 332 is caused. Perform shock absorbing action.

Here, a lubricating member 325b such as grease is applied to the contact portion between the ball 325a and the ball housing 325d, so that the rotation of the ball 325a may be more smoothly performed.

According to another embodiment of the present invention as described above it is possible to obtain the effect of improving the safety of the device is installed a rotating shaft. In addition, the impact and heat generation is reduced by the rotatable ball to improve the durability and operation reliability of the product, it is possible to obtain the effect of extending the life of the product.

The present invention prevents the collision between the bearing and the rotating body during abnormal operation of the device, thereby improving the durability and operation reliability of the product, and has the effect of extending the life of the product.

Claims (14)

An air foil bearing supporting a rotating body rotating at a high speed; A housing in which the air foil bearing is accommodated; And Impact damping system of the air foil bearing including an impact damping member protruding in the direction of the rotating body on the inner side of the housing. The method of claim 1, And the length of the shock damping member is smaller than a difference between the distance between the housing and the rotating body and the maximum axial displacement of the rotating body during steady state operation. The method of claim 1, The said shock damping member is a shock damping system of the air foil bearing formed in the point where the vertical distance from the rotating shaft of the said rotating body becomes the minimum. The method of claim 1, The impact damping member includes a contact member in contact with the rotating body, and an elastic member disposed between the housing and the contact member. The method of claim 4, wherein And the contact member is formed of an elastic material. The method of claim 1, The shock damping member is a shock damping system of the air foil bearing comprising a gas injection pipe in which gas is injected. The method of claim 6, And a protrusion formed to protrude from the housing to receive the gas injection pipe therein and formed of an elastic material. The method of claim 6, Shock damping system of the air foil bearing in which the cool air is injected in the gas injection pipe. The method of claim 1, And the impact damping member comprises a ball to enable rolling friction between the rotor and the impact damping member upon contact with each other. The method of claim 9, And a lubrication member is applied between the housing and the ball to smoothly rotate the ball. An air foil bearing supporting a rotating body rotating at a high speed; A housing having a bearing accommodation portion formed therein; And And a shock absorbing member formed between the air foil bearing and the rotating body to cushion an impact generated when the rotor and the air foil bearing collide with each other. The method of claim 11, And the shock absorbing member is spaced apart from the rotating body in the normal operation of the rotating body. The method of claim 11, And the shock absorbing member is configured to prevent contact between the rotor and the air foil bearing during abnormal operation of the rotor. The method of claim 11, And the shock absorbing member is formed on the opening side of the bearing accommodation portion.

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