KR20000065624A - Gas bearing structure for turbo compressor - Google Patents

Abstract

PURPOSE: A gas bearing structure of a turbo compressor is provided to prevent the damage of the parts by stably supporting a driving shaft, thereby improving the reliability of the compressor. CONSTITUTION: A gas bearing structure of a turbo compressor includes an airtight container(10) having compressing chambers(11,12) communicating with each other at both sides and a driving motor(20) between the compressing chambers, a driving shaft(30) combined with the rotator of the driving motor for transmitting a driving force, impellers(40,50) mounted on the both ends of the driving shaft to centrifugally compress the fluid, bearing members(110) mounted on the inside of the airtight container for supporting load of the radius diameter and axial directions of the driving shaft, a radial bearing bush inserted into the outer peripheral surface of the driving shaft and the inner peripheral surface of the bearing member with having a gas passage for buffing to support the rolling of the driving shaft with a high-pressure compressed gas.

Description

GAS BEARING STRUCTURE FOR TURBO COMPRESSOR}

The present invention relates to a gas bearing of a turbo compressor, and more particularly, to a gas bearing structure of a turbo compressor which can prevent the parts from being damaged by preventing the shock from being transmitted to the drive shaft even when the compressor is impacted from the outside.

In general, a compressor compresses a gas such as air or refrigerant gas by a rotary motion of a vane or a rotor or a reciprocating motion of a piston, and generates a gas by a power generating unit for driving the vane or a rotor or a piston and a driving force transmitted from the power generating unit. Compressor part to suck and compress.

These compressors are classified into rotary, reciprocating, linear, scroll, and turbo compressors according to the structure for compressing the gas. Among them, the turbo compressor is an air compressor, which is easy to handle, simple in structure, and airy. The advantage is that the flow is constant.

The turbo compressor is largely divided into a centrifugal compressor and a turbine type axial compressor, and the present invention relates to a centrifugal turbo compressor (hereinafter, referred to as a turbo compressor).

1 is a longitudinal sectional view showing an example of a conventional two-stage compressed turbo compressor.

As shown in the related art, the conventional two-stage compression type turbo compressor has a hermetically sealed container including a first compression chamber 11 communicating with an evaporator (not shown) and a second compression chamber 12 communicating with a condenser (not shown). 10, respectively, formed on both sides, and a motor chamber 13 to which an axial type BELDC motor 20 is mounted is formed at the inner center of the sealed container 10, wherein the first, The second compression chambers 11 and 12 and the motor chamber 13 communicate with each other by the first and second gas flow paths (not shown), and both ends of the driving shaft 30 which are coupled to the motor 20 to rotate are respectively. The first and second compression chambers 11 and 12 are inserted into the first and second compression chambers 11 and 12, respectively, and compress the refrigerant gas sucked while rotating in the first and second compression chambers 11 and 12 into two stages, respectively. Impellers 40 and 50 are coupled.

In addition, both sides of the drive shaft 30 is provided with a bearing portion of the gas bearing for supporting the radial and axial direction of the drive shaft 30, the bearing portion is provided with a bearing member 60 on both sides of the motor chamber (13) The inner peripheral surface is fixed to each other to form a radial bearing surface 61 together with the outer peripheral surface of the drive shaft 30, the inner surface of each bearing member 60, the outer side of the bearing bush 31 formed on both sides of the drive shaft 30 Coupled with the side to form a thrust bearing surface 62, the radial bearing surface 61 is provided on both sides on the outside of the motor chamber 13 than the thrust bearing surface 62, respectively.

In the figure, reference numeral 10a denotes an inlet port, 10b denotes a discharge port, 11a and 12a denote first and second diffusers, 11b and 12b denote first and second volutes, and 11c and 12c denote shrouds. The stator and 22 is the rotor.

The conventional two-stage compression turbocompressor configured as described above is operated as follows.

That is, when induction magnetism is generated in the motor 20 by the applied power source, the drive shaft 30 starts to rotate at a high speed by the induction magnetism and is fixed to both ends of the drive shaft 30. 2 The impellers 40 and 50 rotate, and the refrigerant gas is sequentially sucked into the compression chambers 11 and 12 by the rotation of the impellers 40 and 50 so that the centrifugal force of each impeller 40 and 50 is increased. It is sprayed in the form of a screw through the diffusers (11a, 12a) through each of the volute (11b, 12b), which is pressed through the first diffuser (11a) and the first volute (11b) In the process of flowing into the second diffuser 12a and the second volute 12b, the refrigerant gas is completely compressed by the rise of the pressure head and discharged to the condenser (not shown) through the discharge port 10b.

Here, the drive shaft 30 is seated on the inner circumferential surface of the bearing member 60 when the compressor is stopped, and the outer circumferential surface of the drive shaft 30 and the inner circumferential surface of the bearing member 60 are radial bearing surfaces 61 when the compressor is restarted. In this case, several gas inlet grooves (not shown) are formed on the outer circumferential surface of the drive shaft 30 opposite to the inner circumferential surface of the bearing member 60 when the drive shaft 30 is rotated. The fluid inside flows smoothly between the radial bearing surface 61 of the bearing member 60 and the radial bearing surface (unsigned) of the drive shaft 30.

Meanwhile, a pressure difference is generated between the first compression chamber 11 and the second compression chamber 12 so that this pressure difference pushes the drive shaft 30 from the second compression chamber 12 toward the first compression chamber 11. However, this force was that the drive shaft 30 is stably supported by the thrust bearing surface 62 of the bearing member 60 and the thrust bearing surface 31a of the bearing bush 31 when the compressor is restarted.

However, in the gas bearing of the conventional turbo compressor as described above, part of the refrigerant gas ejected from each impeller (40, 50) and centrifugally compressed leaks toward the rear surface of the impeller (40, 50), so that the inner peripheral surface of the bearing member (60). And an opposing surface between the outer circumferential surface of the drive shaft 30 to serve as a gas bearing, or when the compressor is shaken due to an impact from the outside, the impellers 40 and 50 rotating at high speed are shroud 11c. 12c) or the like, or the drive shaft 30 hits the bearing member 60, and thus the compressor itself may be damaged.

Accordingly, the present invention has been made in view of the problems of the gas bearing of the conventional turbo compressor as described above, so that even if the compressor is shaken by the impact from the outside, the impeller or bearing member does not collide with other parts to be damaged. It is an object of the present invention to provide a gas bearing structure of a turbocompressor.

1 is a longitudinal sectional view showing an example of a conventional turbo compressor.

Figure 2 is a longitudinal sectional view showing a detail "A" of Figure 1;

Figure 3 is a longitudinal sectional view showing an example of a turbo compressor provided with a gas bearing of the present invention.

4A and 4B are a longitudinal sectional view and a perspective view showing an example of the portion “B” of FIG. 3.

5A and 5B are longitudinal sectional views and perspective views showing details of modifications to the “B” portion of FIG. 3;

6A and 6B are longitudinal sectional views and perspective views showing details of modifications to the “B” portion of FIG. 3;

** Description of symbols for the main parts of the drawing **

30: drive shaft 31: thrust bearing bush

110: bearing member 111: bush mounting groove

120,200,300: Shock absorbing bearing bush 130: Porous wire mesh

210,310: buffer gas passage 320: gas through hole

121,220,330: Drive shaft through hole

In order to achieve the object of the present invention, the compression chamber is formed in communication with both sides of the airtight container is formed between the motor chamber is formed between the drive motor, and the drive shaft coupled to the mover of the drive motor to transfer the driving force And an impeller mounted at both ends of the drive shaft and provided in each compression chamber so as to centrifugally compress the fluid, a bearing member mounted inside the sealed container to support radial and axial loads of the drive shaft, and the impeller. Turbo compressor including a radial bearing bush inserted between the outer circumferential surface of the drive shaft and the inner circumferential surface of the bearing member to provide a buffer gas flow path through which a portion of the compressed gas flows to support the swing of the drive shaft by the high-pressure compressed gas centrifugally compressed. A gas bearing structure is provided.

Hereinafter, a gas bearing structure of a turbo compressor according to the present invention will be described in detail with reference to an embodiment shown in the accompanying drawings.

3 is a longitudinal sectional view showing an example of a turbo compressor provided with the present invention gas bearing, Figures 4a and 4b is a longitudinal sectional view and a perspective view showing an example of the "B" portion of Figure 3, Figures 5a and 5b 3 is a longitudinal cross-sectional view and a perspective view showing a modification of the portion "B" of Figure 3, Figure 6a and 6b is a longitudinal cross-sectional view and a perspective view showing a modification of the "B" portion of FIG.

As shown in this, in the two-stage compression type turbocompressor equipped with the gas bearing according to the present invention, the first compression chamber 11 and the second compression chamber 12 are formed inside both sides of the sealed container 10, A motor chamber 13 in which the drive motor 20 is mounted is formed therebetween, and both ends of the drive shaft 30 integrated with the drive motor 20 are rotated in each of the compression chambers 11 and 12 described above. The first impeller 40 and the second impeller 50 for sucking and compressing gas are coupled to each other, and bearing portions are provided between both sides of the driving motor 20 and the impellers 40 and 50 to provide a driving shaft 30. It is configured to support radial and axial loads of.

The bearing portion has a radial bearing surface 110 is fixed to each side of the motor, respectively, its inner circumferential surface to support a radial load along with the outer circumferential surface of the drive shaft 30, the respective bearing members 110 The inner side surface of the thrust bearing bush 31 is integrally coupled to the drive shaft 30 is formed by forming a thrust bearing surface for supporting the axial load.

Here, the radial bearing surface is a buffer bearing bush 120 is inserted into the adverb insertion groove 111 of the bearing member 110, the inner circumferential surface of the bearing member 110 and the buffer bearing bush 120 Between the outer circumferential surface of the impingement (40, 50) is a buffered gas flow path to be introduced into the outer circumferential surface of the drive shaft (30) forming a radial bearing surface (unsigned), while a portion of the high-pressure compressed gas sprinkled by the impeller (40, 50) Symbol) is formed.

The buffer gas flow path is formed by restricting the inflow of gas by interposing a porous wire mesh 130 of ceramic material as shown in FIGS. 4A and 4B, or the buffer as shown in FIGS. 5A and 5B. A plurality of gas inlet grooves 210 are formed on an outer surface of the bearing bush 200, or as shown in FIGS. 6A and 6B, gas inflows on an outer circumferential surface of the buffer bearing bush 300. The groove 310 is formed and a gas through hole 320 is formed which communicates from the gas inlet groove to the inner circumferential surface thereof.

On the other hand, the thrust bearing surface is made of the outer surface of the bearing bushing 31 for the thrust is pressed into the outer peripheral surface of the drive shaft 30 to face the inner surface of the bearing member 110 and the inner surface of the bearing member 110. .

In the drawings, the same reference numerals are given to the same parts as in the prior art.

In the figure, reference numeral 10a denotes an inlet port, 10b denotes a discharge port, 11a and 12a denote first and second diffusers, 11b and 12b denote first and second volutes, and 11c and 12c denote shrouds. A stator, 22 is a rotor, 121 and 131 and 220 and 330 are drive shaft through holes.

The turbo compressor equipped with a gas bearing structure according to the present invention as described above is operated as follows.

That is, the refrigerant gas sucked into the first compression chamber 11 of the hermetic container 10 is centrifugally compressed in one stage by the first impeller 40, and the pressure gas compressed in the first stage is compressed in the second compression chamber 12. 2) is discharged while being centrifugally compressed by the second impeller 50, and a part of the high pressure compressed gas discharged during the centrifugal compression is composed of the bearing member 110 and the buffer bearing bushes 120, 200 and 300. The gas flow path (unsigned) 210 (310, 320) is introduced into the radial bearing surface between the outer peripheral surface of the drive shaft 30 and the inner peripheral surface of the buffer bearing bushes (120, 200, 300) to support the radial load.

In this way, the compressed gas flowing into the radial bearing surface is a high-pressure compressed gas centrifugally compressed by each impeller 40 and 50, so that the drive shaft 30 of the compressor is shaken even when the compressor is shaken by an external shock. The driving shaft 30 is firmly supported by the high pressure compressed gas filled in the radial bearing surface so that the driving shaft 30 does not oscillate, and the high pressure gas flowing into the thrust bearing surface from the radial bearing surface receives the axial load of the driving shaft 30. Will be supported.

At this time, when the porous wire mesh 130 is interposed in the buffer gas flow path (unsigned) 210, 310, and 320, the clearance for the assembly tolerance of the bearing member 110 and the buffer bearing bush 120 is increased. Since the bearing member 110 and the bearing bush 120 can be easily manufactured and assembled, the gas inlet groove 210 is formed on the outer surface of the shock absorbing bearing bush 200. Manufacturing and assembly is relatively difficult due to the small tolerance, but it is possible to ensure the stability of the drive shaft while maintaining a minimum amount of leakage of compressed gas without adding a separate member such as a porous wire mesh 130.

As described above, in the gas bearing structure of the turbocompressor according to the present invention, a part of the high-pressure compressed gas centrifugally compressed by an impeller integrally coupled to both ends of the drive shaft is introduced into the bearing member supporting the drive shaft and compressed. By inserting a radial bearing bush with a buffer gas passage in the bearing member to prevent the drive shaft from swinging under the pressure of the gas, the drive shaft is stably supported even if the compressor is shaken by an impact from the outside to impeller or bearing. There is an effect of improving the reliability of the compressor by preventing other parts such as members from being broken while being bumped.

Claims (4)

Compression chambers are formed in communication with both sides, and a sealed container in which a motor chamber in which a driving motor is mounted is formed, a driving shaft coupled to a mover of the driving motor to transmit driving force, and mounted at both ends of the driving shaft to provide fluid. An impeller provided in each compression chamber for centrifugal compression, a bearing member mounted inside the sealed container to support radial and axial loads of the drive shaft, and a high pressure compressed gas centrifugally compressed by the impeller A gas bearing structure of a turbocompressor including a radial bearing bush inserted between the outer circumferential surface of the drive shaft and the inner circumferential surface of the bearing member, the buffer gas passage in which a portion of the compressed gas flows to support swinging. 2. The gas bearing structure of a turbo compressor according to claim 1, wherein the buffer gas flow passage is provided with a porous member so as to restrict the inflow of gas. 2. The gas bearing structure of a turbocompressor according to claim 1, wherein the buffer gas flow passage is formed with a plurality of gas inflow grooves on an outer surface of the radial bearing bush. The gas bearing structure of a turbocompressor according to claim 1, wherein the buffer gas flow passage forms a gas through hole communicating from the outer peripheral surface to the inner peripheral surface of the radial bearing bush.