KR100273373B1 - Apparatus for fixing impeller for turbo compressor - Google Patents

Abstract

PURPOSE: An apparatus for fixing impeller for turbo compressor is provided to allow the bearing to be easily manufactured, while achieving improved compressor efficiency by reducing a friction loss between the rear surface of the impeller and a high pressure gas. CONSTITUTION: A turbo compressor comprises a plurality of impellers(400,500) which are fixed, in a face-to-face manner, at both ends of a driving shaft(300) so as to compress a fluid. Both ends of the driving shaft are coupled integrally to each impeller, in such a manner that both ends of the driving shaft are not exposed to the rear surfaces of impellers when projected in flank of each impeller. The driving shaft has small diameter portions(310) formed at both ends of the driving shaft, and impellers have through holes(410,510) formed at centers of impellers so as to allow small diameter portions of the driving shaft to be inserted into through holes. Fixing nuts(610,620) are press fit into ends of through holes, and small diameter portions have screw portions(311) formed at ends of small diameter portion so as to be coupled with fixing nuts.

Description

Impeller fixing structure of turbo compressor

The present invention relates to an impeller fixing structure of a turbocompressor, and more particularly, to an impeller fixing structure of a turbocompressor in which an end portion of a drive shaft is fastened inside an impeller.

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 sectional view schematically showing the configuration of a two-stage compression turbocompressor, the inventor of which has been filed with the patent number 97-64568, as shown here, the two-stage compression turbocompressor is generally accumulator ( The first compression chamber 11 in communication with each other (not shown) and the second compression chamber 12 in communication with the normal condenser (not shown) are formed on both sides of the hermetically sealed container 10, respectively. A motor chamber 13 in which an axial type brushless DC motor 20 is mounted is formed at an inner center thereof, and the first and second compression chambers 11 and 12 and the motor chamber 13 are formed. Both ends of the driving shaft 30, which are in communication with each other by the gas flow passage 14 and are coupled to the motor 20 and rotated, are respectively inserted into the first and second compression chambers 11 and 12, and the first ends of the driving shafts 30 are respectively inserted. The 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, a radial bearing 60 for supporting the vertical direction of the drive shaft 30 is coupled to both sides of the drive shaft 30, that is, both sides of the motor 20, and one side of the radial bearing 60. The outer thrust bearing 70 for supporting the axial direction of the drive shaft 30 is coupled.

Here, as shown in FIG. 2, the first and second impellers 40 and 50 are formed to have a smaller outer diameter than the inner diameter through which the gas is compressed, as shown in FIG. It is fixed in an inverted cone shape.

In more detail, through-holes 40a and 50a through which the drive shaft 30 can pass are formed at the centers of the impellers 40 and 50, respectively, and drive shafts through the through-holes 40a and 50a ( Small ends 31 are formed at both ends of step 30, respectively, and threaded portions 31a are formed at ends of the small diameter parts 31, respectively, and pass through the through holes 40a and 50a. 32).

In addition, fixing nuts 32A and 32B are provided on the wall surfaces of the compression chambers 11 and 12 of the airtight container 10, that is, on the inner wall surfaces of the compression chambers 11 and 12 facing the rear surfaces of the impellers 40 and 50. The nut insertion grooves 11A and 12A are formed deeper than the width of.

In the drawings, reference numeral 10a denotes an inlet port, 11a and 12b denotes a first and a second diffuser, 11b and 12b denote a first and a second vortex, 13a denotes an inlet hole, 13b denotes an outlet hole, and 14 and 15 denote first and second 2 gas flow paths, 16 are discharge ports.

The two-stage compression type turbocompressor of the present invention configured as described above is operated as follows.

That is, when the induction magnet is generated in the motor unit 20 by the applied power, the drive shaft 30 starts to rotate at a high speed by the induction magnet and is fixed to both ends of the drive shaft 30. 2 Impellers 40 and 50 rotate, and the refrigerant gas is sequentially sucked into each of the compression chambers 11 and 12 by the rotation of the impellers 40 and 50, and then each of the impellers 40 and 50 It is sprinkled in a screw form by centrifugal force and flows into each volute 11b and 12b through each diffuser 11a and 12a. The refrigerant gas was converted into compressed gas by the rise of the pressure head and discharged to the condenser (not shown) through the discharge port 10b.

In general, however, shortening the length of the drive shaft can reduce the instability of the drive due to the centrifugal force, and can facilitate the design of the radial bearing 60. Since the fastening nuts 32A and 32B are fastened to the backs of the impellers 40 and 50, the drive shaft 30 is not only long but also increases the number of parts according to the use of the fastening nuts 32A and 32B and the center of gravity of the shaft. There is a problem that the centrifugal force increases away from the center, and thus the design of the radial bearing 60 is not easy.

In addition, the back surface area of each impeller 40, 50 is widened by the surface area of the fixing nuts 32A, 32B, so that the contact area with the compressed gas that penetrates the gap of the compression chamber 11, 12 wave becomes wider. There was also a growing problem.

Therefore, the present invention has been devised in view of the problems of the impeller fixing structure of the prior application, minimizing the centrifugal force by shortening the length of the drive shaft to a minimum, as well as pulling the center of gravity to the center of the drive shaft to load the radial bearing It is an object of the present invention to provide an impeller fixing structure of a turbocompressor that can be minimized.

In addition, it is an object of the present invention to provide an impeller fixing structure of the turbocompressor that can minimize the frictional loss caused by contact with the pressurized shaft gas by minimizing the back surface area of each impeller.

1 is a longitudinal sectional view showing an example of a pre- filed turbocompressor.

2 is a longitudinal sectional view showing a fixed structure of an impeller in a turbocharger of a pre- filed.

3 is a longitudinal sectional view showing a fixing structure of an impeller in a turbocompressor according to the present invention.

4 is a longitudinal sectional view showing a modification of the impeller fixing structure in the turbocompressor according to the present invention.

* Explanation of symbols for main parts of the drawings

300: drive shaft 310: small diameter portion

311: thread portion 400, 500: first and second impeller

410,510: Through hole of each impeller 610,620: Fixing nut

In order to achieve the object of the present invention, a turbo compressor in which a plurality of impellers for centrifugally compressing a fluid are coupled so that each suction end faces each other at both ends of the drive shaft; Both ends of the drive shaft is provided with an impeller fixing structure of the turbocompressor, which is integrally coupled in the interior of each impeller so as not to be exposed to its rear surface when projecting each impeller.

Hereinafter, the impeller fixing 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 sectional view showing a fixing structure of the impeller in the turbocompressor according to the present invention, and FIG. 4 is a longitudinal sectional view showing a modification of the impeller fixing structure in the turbocompressor according to the present invention.

First, as shown in FIG. 1 and FIG. 3, the turbo compressor according to the present invention is formed such that the first and second compression chambers 11 and 12 communicate with each other on both sides of a conventional sealed container 10. On the other hand, in the center, the motor chamber 13 for mounting the axial DC motor 20 of which both the stator 21 and the rotor 22 are disc-shaped is formed, and the rotor of the motor 20 22) The driving shaft 300 is press-fitted in the center thereof, and the first and second impellers inserted into the first and second compression chambers 11 and 12 at both ends of the driving shaft 300 to increase the kinetic energy of the refrigerant ( 400 and 500 are fixed in a face-to-face type such that each suction end faces each other, and the radial bearing 60 and the thrust for supporting the radial and axial directions of the drive shaft 300 are provided inside the motor chamber 13. Bearing 70 is installed.

Both ends of the drive shaft 300 are inserted in the rear direction at the suction end of each of the impellers 400 and 500, but both ends thereof are integrally coupled in a range that does not protrude from the rear surface of each of the impellers 400 and 500.

To this end, small diameter portions 310 are formed at both ends of the driving shaft 300, and through holes 410 and 510 are formed at the centers of the impellers 400 and 500 to penetrate the small diameter portions 310 of the driving shaft 300. Fixing nuts 610 and 620 are press-fitted to the ends of the through holes 410 and 510, and screw portions 311 are formed at the ends of the small-diameter portions 310 of the drive shaft 300 to be fastened to the fixing nuts 610 and 620. do.

The general operation of the turbocompressor according to the invention as described above is the same as in the prior application.

That is, the driving shaft 300 and the impellers 400 and 500 are rotated by the applied power, and refrigerant is introduced into the motor chamber 13 from the evaporator or accumulator of the refrigeration cycle apparatus, and the introduced refrigerant is a motor ( After cooling 20, the gas flows out into the first gas passage 14 again, and the refrigerant gas introduced into the first gas passage 14 is temporarily compressed while being scattered by the first impeller 400. The compressed and compressed refrigerant gas is again sucked into the second impeller 500 through the second gas passage 15, and is completely compressed into two stages while being scattered again and discharged to the refrigeration cycle apparatus (exactly, a condenser).

As described above, the turbo compressor sucks and compresses the refrigerant in the process of rotating the driving shaft 300 at high speed together with the motor 20. Since the driving shaft 300 is fastened and fixed inside the impellers 400 and 500, As a result, the length of the drive shaft 300 is shortened, so that the centrifugal force generated during the rotation is reduced, as well as the center of gravity is driven to the center to facilitate the design of the radial bearing 60.

In addition, since the driving shaft 300 does not protrude on the back surface of each impeller 400, 500, the contact area between each impeller 400, 500 and the compressed gas is minimized, thereby reducing the frictional loss between the compressed gas and improving the performance of the compressor. It will be.

The case of the modification by this invention is as follows.

That is, in the above-described example, the fixing nuts 610 and 620 are press-fitted to the centers of the rear surfaces of the impellers 400 and 500, and both ends of the drive shaft 300 are fastened to the fixing nuts 610 and 620. As shown in the figure, a threaded portion 310A is formed at both ends of the drive shaft 300A, and through-holes 410A and 510A through which the drive shaft 300A is inserted are inserted into the centers of the impellers 400A and 500A. The inner circumferential surfaces of the through holes 410A and 510A are formed with screw portions 411A and 5117 for fastening the screw portion 310A of the drive shaft 300A.

This can reduce the length of the drive shaft shorter in addition to the above-described effects in the above-described modification, and can also reduce the number of parts without using a separate fixing nut.

As described above, the impeller fixing structure of the turbocompressor according to the present invention is integrally coupled in a range in which both ends of the drive shaft do not protrude from the rear surface of each impeller, thereby shortening the length of the drive shaft and stably supporting it. The bearing can be easily manufactured, and the contact area with the high pressure gas is reduced at the back of the impeller, thereby reducing the friction loss, thereby improving the compressor efficiency, and eliminating the fastening nut for fixing the drive shaft and the impeller, thereby reducing the number of parts. The production cost is reduced.

Claims (3)

In a turbocompressor, a plurality of impellers for centrifugally compressing a fluid are coupled so that each suction end faces each other at both ends of the drive shaft; Impeller fixing structure of the turbocompressor, characterized in that the both ends of the drive shaft is integrally coupled in the interior of each impeller so as not to be exposed to the back when the side projection of each impeller. According to claim 1, Small diameter portion is formed at both ends of the drive shaft, the through-hole through the small diameter portion of the drive shaft is formed in the center of each impeller, the fixing nut is pressed in the end of each through hole, each small diameter portion of the drive shaft An impeller fixing structure of a turbocompressor, characterized in that a screw portion is formed at an end of the screw and is fastened to each fixing nut. According to claim 1, wherein a screw portion is formed in both ends of the drive shaft, the through-hole is formed through the drive shaft in the center of each of the impeller, the inner circumferential surface of the through hole is formed with a screw portion is fastened to the screw shaft of the drive shaft and the drive shaft and Impeller fixed structure of the turbocompressor, characterized in that the impeller is directly screwed.

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