KR100273377B1 - Bearing structure for turbo compressor - Google Patents

Abstract

PURPOSE: A bearing structure for turbo compressor is provided to reduce weight and size of the compressor by reducing the parts count of the compressor. CONSTITUTION: A turbo compressor comprises a closed container(10) having a first compression chamber and a second compression chamber communicated to each other; a driving shaft(30) which rotates as being coupled to a rotor of a driving motor fixed to the closed container; a first impeller(140) and a second impeller(150) coupled to both ends of the driving shaft, and which rotate as being inserted into each compression chamber so as to compress the fluid. The compression chamber has a diameter increasing as it goes from an inlet side toward an outlet side of the compression chamber. The impeller inserted into the compression chamber has a diameter increasing as it goes from a refrigerant inlet side toward a refrigerant outlet side. The impellers have blades where cylindrical shroud members(141,151) are fixed, with a predetermined spacing from the inner periphery of the compression chamber. The outer periphery of the shroud member and the inner periphery of the compression chamber form a bearing surface with respect to the vibration of the driving shaft in a radial direction and thrust direction.

Description

Bearing structure of turbo compressor

The present invention relates to a turbocompressor using a centrifugal force by an impeller, and more particularly, to a bearing structure of a turbocompressor which simultaneously supports radial and axial directions of a drive shaft.

In general, a compressor is a machine that compresses 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 is a power generator for driving a vane, a rotor, and a piston, and a driving force transmitted from the power generator. It consists of a compressor mechanism for sucking and compressing gas.

The compressor is classified into a sealed type or a separate type according to the arrangement of the power generating portion and the compression mechanism portion, wherein the sealed type is a type in which the power generating portion and the compression mechanism portion are installed together in a predetermined sealed container, and the separate type is outside the sealed container. The power generating unit is installed in the driving force generated in the power generating unit is transmitted to the compression mechanism in the sealed container.

The hermetic compressor includes a rotary, reciprocating, linear and scroll compressor according to a structure for compressing gas. In recent years, the impeller is rotated by a driving force of a motor, and the gas is sucked by using a centrifugal force generated when the impeller is rotated. Turbo compressors (or centrifugal compressors) for compression are newly introduced.

1 is a longitudinal cross-sectional view schematically showing the configuration of a two-stage compression turbocompressor, which the inventor has filed with a patent application No. 97-64567. As shown therein, the two-stage compression turbocompressor of the prior application is usually an accumulator ( A first compression chamber 11 in communication with A) and a second compression chamber 12 in communication with a normal condenser (not shown) are formed on both sides of the hermetically sealed container 10, respectively, and inside the hermetically sealed container 10. In the center, a motor chamber 13 to which a brushless DC motor 20 of a radial type is mounted is formed, and the first and second compression chambers 11 and 12 and the motor chamber 13 are gasses. Both ends of the drive shaft 30, which are in communication with each other by the flow path 14 and are coupled to the motor 20 and rotated, are inserted into the first and second compression chambers 11 and 12, respectively, and the first and second ends thereof are respectively inserted into the first and second compression chambers 11 and 12. First and second impellers 40 and 50 for compressing the gas sucked while rotating in the second compression chambers 11 and 12 in two stages are combined.

In addition, radial bearings 60 for supporting the radial direction of the drive shaft 30 are coupled to both sides of the drive shaft 30, that is, both sides of the motor 20, and both sides of the radial bearing 60. The outer thrust bearing 70 for supporting the axial direction of the drive shaft 37 is coupled.

The first and second compression chambers 11 and 12 respectively convert the kinetic energy of the refrigerant accelerated by the first and second impellers 40 and 50 into the positive pressure at their respective outlet sides. It consists of the diffuser 11a, 12a and the 1st, 2nd volute 11b, 12b.

The first and second impellers 40 and 50 are integrally formed with several vanes 40a and 50a having a predetermined curvature, as shown in FIGS. 2 (a) and 2 (b). The outer diameter through which the refrigerant gas is introduced is smaller than the inner diameter through which the gas is compressed, and is fixed in a conical shape based on the driving shaft 30.

In the drawings, reference numeral 10a denotes an inlet port, 10b an outlet port, 13a an inlet hole, 13b an outlet hole, and 41 and 51 are vanes.

The two-stage compression turbocompressor of the prior application configured as described above is operated as follows.

That is, when the induction magnetism is generated in the motor 20 by the applied power, the drive shaft 30 starts to rotate at a high speed by the induction magnetism, so that the first and second fixed to both ends of the drive shaft 30. The impellers 40 and 50 rotate, and the refrigerant gas is sucked into each of the compression chambers 11 and 12 by the rotation of the impellers 40 and 50, and then the centrifugal force of each impeller 40 and 50 It is sprayed in the form of a screw and flows into each volute 11b and 12b through each diffuser 11a and 12a. At this time, the refrigerant gas flows into each volute 11b and 12b via each diffuser 11a and 12a. Was converted into the compressed gas by the rise of the pressure head and discharged to the condenser (not shown) through the discharge port (10b).

In more detail, the refrigerant gas is sucked from the accumulator A into the first compression chamber 11 by the rotation of the first impeller 40 and is accelerated by the first impeller 40, and the accelerated refrigerant gas is First stage compression is performed while entering the first volute 11b through the first diffuser 11a, and the temporary compression gas in which the first stage compression is performed is carried out through the gas passage 14 in the second compression chamber ( 12, and the compressed gas sucked into the second compression chamber 12 is accelerated again by the second impeller 50, the accelerated compressed gas is again the second The second volume was introduced into the second volute 12b through the diffuser 12a and then discharged to the discharge port 10b after two stage compression was performed.

Here, since the drive shaft 30 is in a rotational state in a free state, the radial direction of the drive shaft 30 is supported by each radial bearing 60, while the axial direction of the drive shaft 30 Was supported by each thrust bearing 70.

However, in the above-described turbo compressor of the prior application, since the radial bearing 60 and the thrust bearing 70 and the like are formed as separate structures to support the radial and axial directions of the drive shaft 30, the parts of the compressor As the number increases, the production cost increases, as well as the need for a separate space for each bearing (60, 70) has a problem that the compressor is enlarged and the weight of the entire compressor increases by that much.

Accordingly, the present invention has been made in view of the problems of the above-described prior invention compressor, and reduces the production cost by reducing the number of parts of the compressor, as well as the bearing structure of the turbo compressor can achieve compact and lightweight compressor The purpose is to provide.

1 is a longitudinal sectional view schematically showing a turbocharger of a pre- filed.

2 (a) and 2 (b) are a longitudinal sectional view and a front view showing an impeller of a pre- filed turbocompressor.

3 is a longitudinal sectional view schematically showing a turbocompressor according to the present invention.

4 is a longitudinal cross-sectional view showing the detail 'A' of FIG.

5 (a) and 5 (b) are a longitudinal sectional view and a front view showing the impeller of the turbocompressor of the present invention.

6 is a distribution diagram of forces shown to explain the bearing of the turbocompressor of the present invention.

* Explanation of symbols for main parts of the drawings

11,12: 1st, 2nd compression chamber 140,150: 1st, 2nd impeller

140a, 150a: Wing difference of each impeller 141,151: Shroud of each impeller

In order to achieve the object of the present invention, the first compression chamber and the second compression chamber is formed in communication with each other on both sides, the drive shaft coupled to the rotor of the fixed drive motor of the sealed container and rotated, A turbocompressor including a first impeller and a second impeller coupled to both ends of the drive shaft and inserted into each compression chamber to rotate and receive centrifugal pressure under different pressure. The compression chamber is formed so that its diameter gradually increases from the inlet side to the outlet side during side projection, and the impeller inserted into the compression chamber is also formed so that its diameter gradually increases from the suction end to the discharge end during the axial projection. The cylindrical shroud member is fixed to the wing side end at a predetermined distance from the inner circumferential surface of the compression chamber, and the outer circumferential surface of the shroud member and the inner circumferential surface of the compression chamber opposite thereto are bidirectional bearings for radial and thrust vibration of the drive shaft. Provided is a bearing structure of a turbocompressor, characterized in that it is made into a surface.

Hereinafter, the bearing structure of the turbocompressor according to the present invention will be described in detail based on the embodiment shown in the accompanying drawings.

3 is a longitudinal cross-sectional view schematically showing a turbo compressor according to the present invention, and FIG. 4 is a longitudinal cross-sectional view showing part 'A' of FIG. 3 in detail. FIGS. 5 (a) and 5 (b) are turbo turbo compressors of the present invention. A longitudinal sectional view and a front view showing the impeller of.

As shown therein, the turbocompressor according to the present invention has a radial type bieldimotor 20 mounted on the inner center of the hermetic container 10, and the first and second parts of the hermetic container 10 are provided on both sides of the hermetic container 10. Compression chambers 11 and 12 are formed to communicate with each other, and both ends of the driving shaft 30 which are coupled to the motor 20 to rotate are inserted into the first and second compression chambers 11 and 12, respectively. Each end of the drive shaft 30 is configured by rotatably coupling the first and second impellers 140 and 150 having a larger inner diameter than the outer diameter.

The first and second compression chambers 11 and 12 are curved to gradually increase in diameter from the inlet side to the discharge side during side projection, and the first and second compression chambers 11 and 12 are formed at the outlet sides of the compression chambers 11 and 12. The first and second diffusers 11a and 12a and the first and second volutes 11b and 12b for converting the kinetic energy of the refrigerant accelerated by the two impellers 140 and 150 into the static pressure are provided.

The first and second impellers 140 and 150 are curved to gradually increase in diameter from the suction end to the discharge end during side projection so as to correspond to the compression chambers 11 and 12, and rotate on the outer circumferential surface of the impeller body. A plurality of vanes 140a and 150a are formed to protrude and have a predetermined curve so as to suck and discharge the fluid, and at the wing side ends of each of the impellers 140 and 150, the inner peripheral surfaces of the compression chambers 11 and 12 and the predetermined intervals are separated. The cylindrical shrouds (141, 151) are integrally fixed to face each other.

In the drawings, the same reference numerals are given to the same parts as in the previous application.

In the drawings, reference numeral 13 denotes a motor room, an inflow hole of 13a, and an outflow hole of 13b.

The bearing structure of the turbocompressor according to the present invention as described above is operated as follows.

That is, when the driving shaft 30 and each of the impellers 140 and 150 are rotated by the applied power, the first impeller 140 of which the refrigerant gas is sucked to the first diffuser 11a and the first volute 11b. It is temporarily compressed while being scattered, and the compressed refrigerant gas is again sucked into the second impeller 150 to be completely compressed in two stages in the second diffuser 12a and the second volute 12b, and the refrigeration cycle is performed. Discharged to the device (exactly the condenser).

Here, while the pressure of the first compression chamber 11 is relatively low compared to the pressure of the second compression chamber 12, the drive shaft 30 including the impellers 140 and 150 is located on the second compression chamber 12 side. While receiving an axial load toward the first compression chamber 11 side and being loaded radially by the centrifugal force generated when the drive shaft 30 is rotated, the axial load and the radial load of the drive shaft 30 are Is supported by the respective X and Y components generated between the outer circumferential surfaces of both shrouds 141 and 151 and the inner circumferential surfaces of the respective compression chambers 11 and 12.

Looking at this in more detail as follows.

6 is a representative example of the equilibrium state of the force of the first compression chamber side in the two compression chambers, as shown in the first compression chamber through the suction port (10a) of the first compression chamber 10 Most of the refrigerant gas flowing into the chamber 11 is sucked into the first impeller 140 and scattered by the first diffuser 11a and the first volute 11b, while the remaining amount of the refrigerant gas is rotated. The suction gas is sucked between the outer circumferential surface of the shroud 141 and the inner circumferential surface of the first compression chamber 11, and the refrigerant gas sucked between the shroud 141 and the inner circumferential surface of the compression chamber 11 has a component force (Fy) in the vertical direction and The force F combined with the horizontal force Fx is transmitted to the outer circumferential surface of the shroud 141.

At this time, the vertical component force (Fy) serves as a radially applied radial bearing, while the motor 20 and the impellers 140 and 150 support the radial direction of the integrated drive shaft 30, whereas the horizontal direction The component force Fx acts as a pre- filed thrust bearing, and supports the axial bias of the drive shaft 30 due to the pressure difference between the compression chambers 11 and 12.

This process occurs equally between the second compression chamber 12 and the shroud 151 integrated in the second impeller 150, so that the driving shaft 30 is driven stably in the axial direction and the radial direction.

As described above, in the bearing structure of the turbocompressor according to the present invention, each impeller is disposed in the compression chamber, which gradually increases in diameter from the inlet side to the outlet side. In the wing side end of the compression chamber, the inner peripheral surface of the compression chamber is fixed integrally and the radial force and the axial direction of the drive shaft by the force force of the fluid sucked between the outer peripheral surface of the shroud and the inner peripheral surface of each compression chamber. By supporting it, separate radial bearings and thrust bearings are unnecessary, thereby reducing the number of parts, thereby reducing production costs and miniaturizing and reducing the weight of the compressor.

Claims (1)

A hermetically sealed container in which the first compression chamber and the second compression chamber are formed in communication with each other, a drive shaft coupled to and rotated by a rotor of a fixed drive motor of the sealed container, and coupled to both ends of the drive shaft to each compression chamber. In the turbocompressor including a first impeller and a second impeller inserted and rotated to sequentially centrifugally compress the fluid under different pressures; The compression chamber is formed so that its diameter gradually increases from the inlet side to the outlet side during side projection, and the impeller inserted into the compression chamber is also formed so that its diameter gradually increases from the suction end to the discharge end during the axial projection. The cylindrical shroud member is fixed to the wing side end at a predetermined distance from the inner circumferential surface of the compression chamber, and the outer circumferential surface of the shroud member and the inner circumferential surface of the compression chamber opposite thereto are bidirectional bearings for radial and thrust vibration of the drive shaft. Bearing structure of a turbo compressor, characterized in that the surface.

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