KR100320193B1 - Structure for cooling gasbearing of turbo compressor - Google Patents

Abstract

The present invention relates to a gas bearing cooling structure of a turbo compressor, and the present invention relates to a hermetically sealed container in which a compression chamber is formed in communication with each other, and a motor chamber in which a driving motor is mounted therebetween is coupled to a mover of the driving motor. A driving shaft for transmitting a driving force, an impeller provided in each compression chamber so as to be centrifugally compressed to the fluid by being mounted at both ends of the driving shaft, and a bearing mounted in the sealed container to support the driving shaft in the radial and axial directions. Thrust bearings having a heat dissipation portion formed on the back side of the bearing surface so as to increase the cooling efficiency by expanding the area contacted with the drive shaft to form a thrust bearing surface together with the member and the bearing member. By including a bush, each bearing surface supporting the radial and axial loads of the drive shaft is overheated to deform heat. Prevented from occurring by causing it is possible to improve the reliability of the compressor.

Description

STRUCTURE FOR COOLING GASBEARING OF TURBO COMPRESSOR}

The present invention relates to a gas bearing of a turbo compressor, and more particularly, to a gas bearing cooling structure of a turbo compressor which can prevent overheating of each bearing surface.

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 therein, the conventional two-stage compression turbo compressor includes 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 drawings, 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, 14 denotes a sealing member, and 21 denotes a stator. , 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. ) To support the radial load of the drive shaft 30 by sucking the gas in the motor chamber 13.

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, when the compressor restarts, the inner surface of the bearing member 60 and the outer surface of the bearing bush 31 form a thrust bearing surface 62 while inhaling gas that has passed through the radial bearing surface 62 to drive the shaft 30. ) To support the axial load.

However, in the gas bearing of the conventional turbo compressor as described above, the members 30, 60, 31, 60 come into contact with the radial bearing surface 61 as well as the thrust bearing surface 62 during the high speed operation of the compressor. If not, the frictional heat is generated by the contact of the gas, if the frictional heat is not smoothly cooled, the bearing member 60 and the coating surface (unsigned) softened, there was a fear that the bearing portion is 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, to prevent the radial bearing surface or the thrust bearing surface from overheating to prevent the bearing member and coating surface from being damaged. It is an object of the present invention to provide a gas bearing cooling structure of a turbo compressor.

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

Figure 2 is a longitudinal sectional view showing the 'A' portion of FIG.

Figure 3 is a 'B-B' of Figure 2, a front view showing the back of the bearing bush.

4 is a longitudinal sectional view showing an example of the present invention turbocompressor.

5 is a longitudinal sectional view showing an example of the portion 'C' of FIG.

Figure 6 is a 'D-D' of Figure 5, a front view showing the back of the bearing bush.

7 is a longitudinal sectional view showing a modification to the 'C' portion of FIG.

Figure 8 is a 'E-E' of Figure 7, a front view showing the back of the bearing bush.

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

10: sealed container 20: drive motor

40,50: impeller 60: bearing member

61: radial bearing face 62: thrust bearing face

100: drive shaft 110: thrust bearing bush

111: cooling groove 112: cooling fin

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 the drive shaft in the radial direction and the axial direction, and the bearing member And a thrust bearing bush having a heat dissipating portion formed on a rear side of the bearing surface to increase the cooling efficiency by increasing the area contacted with the drive shaft to form a thrust bearing surface and contacting the fluid inside the sealed container. A gas bearing cooling structure of a turbo compressor is provided.

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

Figure 4 is a longitudinal cross-sectional view showing an example of the turbo compressor of the present invention, Figure 5 is a longitudinal cross-sectional view showing an example of the 'C' portion of Figure 4, Figure 6 shows a 'D-D' of Figure 5, the bearing Front view showing the back of the bush.

As shown therein, the two-stage compression turbo compressor equipped with the cooling structure of the gas bearing according to the present invention includes a first compression chamber 11 and a second compression chamber 12 inside both sides of the sealed container 10. And a motor chamber 13 in which the drive motor 20 is mounted therebetween, and at both ends of the drive shaft 100 integrated with the drive motor 20 in each of the compression chambers 11 and 12. The first impeller 40 and the second impeller 50 for sucking and compressing the refrigerant gas while rotating are coupled to each other, and bearing portions are provided between both sides of the driving motor 20 and the impellers 40 and 50. It is configured to support one drive shaft 100 in the radial and axial directions.

The bearing part has an annular bearing member 60 fixed to both sides of the motor chamber 13, and an inner circumferential surface thereof forms a radial bearing surface 61 together with an outer circumferential surface of the drive shaft 100, and each of the bearing members 60. An inner surface of the thrust bearing surface 62 is formed together with an outer surface of the thrust bearing bush 110 coupled to both sides of the drive shaft 30.

Here, not only between the inner circumferential surface of the bearing member 60 constituting the radial bearing surface 61 and the outer circumferential surface of the drive shaft 100 but also the inner surface of the bearing member 60 constituting the thrust bearing surface 62 and the thrust bearing. The outer surfaces of the bush 110 are disposed with a micro clearance therebetween so that fluid flows into the micro clearance during rotation of the drive shaft 100 to serve as a gas bearing. 5 and 6, a plurality of cooling grooves 111 for cooling the heat generated by the contact between the gas and the bearing surface are bent in a forward direction with respect to the rotational direction of the drive shaft 100, or formed in FIG. As shown in FIG. 8, a plurality of cooling fins 112 are bent in the forward direction with respect to the rotational direction of the drive shaft 100 to be embossed on the rear side of the thrust bearing bush 110.

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

In the drawings, 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, 14 denotes a sealing member, and 21 denotes a stator. , 22 is the rotor.

The general operation of the turbo compressor equipped with the gas bearing cooling structure according to the present invention as described above is the same as in the prior art.

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. And centrifugally compressed by the second impeller 50 to be discharged to a refrigeration cycle apparatus, etc., wherein the drive shaft 100 has its own load and the radial direction of the loads of the components coupled to the drive shaft 100. Since the load is transmitted to the radial bearing surface 61 of the bearing member 60 and the refrigerant gas is first compressed in the first impeller 40 and sucked into the second impeller 50, the first compression chamber 11 is applied. A pressure difference is generated between the and the second compression chamber 12 to transfer the axial load due to the pressure difference to the thrust bearing surface 62 of the bearing member 60, but the radial load and the axial load are The drive shaft is supported by the fluid flowing into the radial bearing surface 61 and the thrust bearing surface 62. It is driven stably.

At this time, the fluid flowing into the radial bearing surface 61 and the thrust bearing surface 62 is friction with each bearing surface (61, 62) during rotation of the drive shaft 100 to act as a gas bearing to generate friction heat However, the frictional heat is provided with a cooling groove 111 or a cooling fin 112 formed on the rear side of the bearing bush for thrust 110 so as to enlarge the area in contact with the low temperature fluid in the motor chamber 13. As a result, frictional heat is rapidly dissipated through the cooling groove 61 or the cooling fins 62, thereby preventing the respective bearing surfaces 61 and 62 or even the drive shaft 100 from being thermally deformed.

As described above, the gas bearing cooling structure of the turbocompressor according to the present invention is cooled by widening the area in contact with the low temperature fluid on the back side of the thrust bearing bush which is coupled to the drive shaft and forms a thrust bearing surface together with the bearing member. By forming a heat dissipation portion of the cooling groove or the cooling fin to improve the efficiency, it is possible to prevent the overheating of each bearing surface that supports the radial and axial load of the drive shaft to prevent thermal deformation, thereby improving the reliability of the compressor. .

Claims (3)

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 the drive shaft in the radial direction and the axial direction, and coupled to the drive shaft to form a thrust bearing surface with the bearing member. And a thrust bearing bush having a heat dissipating portion formed on the rear side of the bearing surface to increase the area in contact with the fluid inside the hermetic container to increase the cooling efficiency. The gas bearing cooling structure of claim 1, wherein the heat dissipation portion is formed by engraving a plurality of cooling grooves so as to be curved in a forward direction with respect to the rotational direction of the thrust bearing bush. The gas bearing cooling structure of claim 1, wherein the heat dissipation portion is formed by embossing a plurality of cooling fins so as to be curved in a forward direction with respect to the rotational direction of the thrust bearing bush.