KR100273374B1 - Thrust bearing structure for turbo compressor - Google Patents

Abstract

PURPOSE: A thrust bearing structure for turbo compressor is provided to achieve improved reliability of compressor by allowing the refrigerant gas to be smoothly introduced to the bearing surface formed between support plates and fixed plate, and support the axial movement of the driving shaft. CONSTITUTION: A thrust bearing comprises inner and outer support plates(111,112) coupled to the outer periphery of a driving shaft(30); and a fixed plate(120) interposed between inner and outer support plates so as to form a bearing surface, and formed integrally with the inner periphery of the closed container. The fixed plate has a gas groove(120a) formed at both surfaces of the fixed plate so as to allow a gas to be smoothly introduced to the bearing surface formed between inner and outer support plates and fixed plate. The inner and outer support plates have inner surfaces opposed to both surfaces of the fixed plate, respectively, and the inner surfaces of inner and outer support plates are coated so as to minimize an abrasion loss.

Description

Thrust Bearing Structure of Turbo Compressor

The present invention relates to a thrust bearing of a turbocompressor, and more particularly, to a thrust bearing structure of a turbocompressor with smooth inflow of gas.

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, the inventor of which has been filed with the patent number 97-64568, as shown here, the two-stage compression turbocompressor of the prior application is usually an 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 first and second gas passages 14 and 15 and are coupled to the motor 20 to rotate are inserted into the first and second compression chambers 11 and 12, respectively. The first and second impellers 40 and 50 for compressing the gas sucked while rotating in the first and second compression chambers 11 and 12 in two stages are coupled to the end thereof. There.

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 30 is coupled.

Here, the radial bearing 60 is disposed on both sides of the drive shaft 30 (more precisely, on both sides of the motor), and the bush 61 press-fitted to the outer circumferential surface of the drive shaft 30 includes the bearing housing 62. The inner circumferential surface and the bearing surface are coupled to each other, and the bearing housing 62 is fixed to the inner circumferential surface of the hermetic container 10 by a flexible support member 63.

The thrust bearing 70 is installed on one side of the radial bearing 60 (usually, the second compression chamber side), and the inner outer support plates 71A and 7LB are disposed at a predetermined interval on one outer circumferential surface of the drive shaft 30. In between the inner and outer support plates 71A and 7LB, a fixed plate 72 which is fastened to the inner circumferential surface of the closed air (more precisely, the motor compartment) 10 is inner and outer support plates 71A and 7LB. Are combined to form bearing surfaces, respectively.

The contact surfaces of the inner and outer support plates 71A and 7LB and the fixed plate 72 are precision machined, and the contact surfaces are usually coated with aluminum oxide.

In the drawings, reference numeral 10a denotes an inlet port, l0b denotes a discharge port, 11a and 12a denote first and second diffusers 11b and 12b, and first and second volutes, 21 denotes a stator, and 22 denotes a rotor.

The two-stage compression turbocompressor of the prior application 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 the form of a screw by centrifugal force and flows into each volute 11b and 12b through each diffuser 11a and 12a. At this time, the process flows into each volute 11b and 12b via each diffuser 11a and 12a. At this time, the refrigerant gas was converted into the compressed gas by the rise of the pressure head and was discharged to the condenser (not shown) through the discharge port 10b.

Here, when the drive shaft 30 is rotated or when the refrigerant gas is compressed by the drive shaft 30 and the impellers 40 and 50, the drive shaft 30 receives a force in the radial direction and the axial direction. And the axial direction is supported by the radial bearing 60 and the thrust bearing 70, the thrust bearing 70 of the inner and outer support plates 71A, 71B coupled to the drive shaft 30 is sealed container 10 Since the fixed plate 72 is fastened to a predetermined surface gap, the refrigerant gap is filled with a predetermined amount of refrigerant gas to support the axial direction of the drive shaft 30 while generating a constant reaction force.

However, in the above-described turbo compressor of the prior application, the inner and outer support plates 71A and 7LB of the thrust bearing 70 and the fixed plates 72 which are in contact with each inner surface of the inner and outer support plates 71A and 71B are provided. In order to smoothly lubricate the contact surface with aluminum oxide or the like, this is the opposite surface of the fixed plate 72 facing the inner and outer support plates 71A, 7LB and its inner and outer support plates 71A, 71B. Since all of them are formed to be flat so that a sufficient amount of refrigerant gas does not flow into the gap between the plates, there is a problem in that the axial vibration of the drive shaft 30 cannot be smoothly supported.

Accordingly, an object of the present invention is to provide a thrust bearing structure of a turbocompressor, which is capable of doubling the axial support capacity of the drive shaft. .

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

2 is a longitudinal cross-sectional view of a thrust bearing in detail in a pre- filed turbocompressor.

3 is a longitudinal sectional view of a thrust bearing of a turbocompressor according to the present invention;

4 is a front view showing a fixing plate in the thrust bearing of the turbocompressor according to the present invention.

* Explanation of symbols for main parts of the drawings

10: sealed container 30: drive shaft

111,112: inner and outer support plate 120: fixed plate

120a: gas groove

In order to achieve the object of the present invention, in order to support the axial direction of the drive shaft which is integral to the rotor of the drive motor and the impeller for centrifugally compressing the refrigerant gas in two stages at both ends thereof, one outer peripheral surface of the drive shaft In the thrust bearing of the turbocompressor comprising an inner and outer support plates coupled to each other at predetermined intervals, and a fixing plate interposed between the inner and outer support plates to form a bearing surface and integral with the inner circumferential surface of the hermetic container; remind. Gas grooves are formed on both side surfaces of the fixed plate to facilitate the inflow of gas to the bearing surfaces between the inner and outer support plates and the fixed plate, and on the opposite surfaces of the inner and outer support plates opposite to both sides of the fixed plate, A thrust bearing structure of a turbocompressor is provided, characterized in that the coating surfaces are each formed to minimize frictional losses upon contact.

Hereinafter, the thrust bearing 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 thrust bearing of the turbocompressor according to the present invention, and FIG. 4 is a front view showing a fixing plate in the thrust bearing of the turbocompressor according to the present invention.

The turbocompressor according to the present invention will be described first by referring to FIG. 1 as follows.

Typically, the motor chamber 13 and its motor chamber in which the axial DC motor 20, in which both the stator 21 and the rotor 22 are disc-shaped, is mounted in the center of the sealed container 10 ( 13, first and second compression chambers 11 and 12 are formed on both outer sides of the first application, and both ends of the drive shaft 30 press-fitted to the center of the rotor 21 of the motor 20 are firstly formed. First and second extending to the second compression chamber (11, 12), the first and second to increase the kinetic energy of the refrigerant in the first, second compression chamber (11, 12) at both ends of the drive shaft (30) Impellers 40 and 50 are fixed in an inverted cone shape with reference to drive shaft 30, and radial bearing 60 for supporting radial and axial directions of drive shaft 30 in the motor chamber 13. And thrust bearing 100 is installed.

Here, the thrust bearing 100 is disposed on one side of the drive shaft 30 (more precisely, the second compression chamber side with the motor in the center), and the inner and outer support plates 111 and 112 on one outer peripheral surface of the drive shaft 30. The fixing plate 120 is press-fitted at a predetermined interval, and the fixing plate 120 fastened to the inner circumferential surface of the sealed container (more precisely, the motor chamber) 10 between the inner and outer supporting plates 111 and 112. It is interposed so as to form a bearing surface with the opposite surface of each.

In order for the gas to flow smoothly between the inner and outer support plates 111 and 112 and the fixing plates 120 opposite to the inner surfaces of the inner and outer support plates 111 and 112 to form a gas bearing, both sides of the fixing plate 120 are formed. The plurality of spiral gas grooves 120a are formed to be curved in the same direction.

In addition, it is preferable that the inner surface of the inner and outer support plates 111 and 112 opposite to both surfaces of the fixing plate 120 is coated with aluminum oxide to minimize abrasion loss.

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

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

That is, the drive shaft 30 and the impellers 40 and 50 are rotated by the applied power, and the refrigerant is introduced into the refrigerant suction pipe (not shown) and the inflow from the evaporator (not shown) or the accumulator (not shown) of the refrigeration cycle apparatus. It flows into the interior of the motor chamber 13 through the through hole (13a), and the introduced refrigerant cools the motor 20 and then flows out again into the first gas passage (14) through the outflow hole (13b), The refrigerant gas introduced into the first gas passage 14 is temporarily compressed while being scattered into the first compression chamber 11 by the first impeller 40, and the compressed refrigerant gas is again compressed into the second gas. It is sucked into the second impeller 50 through the flow path 15 and is completely compressed in two stages in the second compression chamber 12 and discharged to a refrigeration cycle apparatus (exactly, a condenser).

At this time, the drive shaft 30 generates a force in the radial direction due to its own load, which is of course supported by the radial bearing 60 installed on both sides of the motor 20, of course, the drive shaft 30 Is also subjected to a force in one or both axial directions due to the pressure difference between the first and second compression chambers (11, 12), the axial force is a thrust bearing (100) coupled to one side of the drive shaft (30) It is supported by) to rotate stably without biasing to either side.

That is, when the drive shaft 30 rotates at high speed, the inner and outer support plates 111 and 112 coupled to the drive shaft 30 rotate together with the drive shaft 30 at high speed, and the inner and outer support plates ( The refrigerant gas inside the motor chamber is sucked along the gas groove 120a of the fixed plate 120 by the high-speed rotation of 111 and 112, and the contact surfaces between the fixed plate 120 and the inner and outer support plates 111 and 112 are opposite to each other. Will be pushed out.

At this time, aluminum oxide is coated on the side surfaces of the inner and outer support plates 111 and 112 opposite to both sides of the fixing plate 120 to minimize frictional losses of the refrigerant gas.

In this way, the inner and outer support plates 111 and 112 are integrated into the drive shaft 30, and the fixing plate 120 between the inner and outer support plates 111 and 112 forming a bearing surface on both sides thereof is integrated into the hermetic container 30. During the high-speed rotation of the inner and outer support plates 111 and 112, the refrigerant gas sucked into the surface gap with the fixing plate 120 pushes the bearing surfaces of the support plates 111 and 112 in both directions, thereby pushing the shaft of the drive shaft 30 with the pushing force. In addition to supporting the direction, spiral gas grooves 120a are formed on both sides of the fixing plate 120 so that the gas is sufficiently introduced, so that the effect of the gas bearing is further improved.

The gas groove and the coating surface may be formed on opposite surfaces, respectively.

As described above, in the thrust bearing structure of the turbocompressor according to the present invention, the inner and outer support plates are coupled to the outer circumferential surface of one side of the drive shaft at predetermined intervals so as to support the axial direction of the drive shaft integrated with the drive motor. A fixed plate having gas inlet grooves formed on both sides of the outer support plate is integrated with the inner circumferential surface of the sealed container, so that the refrigerant gas flows smoothly into the bearing surface between the inner and outer support plates and the fixed plate, thereby reducing the axial fluctuation of the drive shaft. Since it supports, the reliability of the compressor is remarkably improved.

Claims (2)

In order to support the axial direction of the drive shaft which is integrated with the rotor of the drive motor and the impeller for centrifugally compressing the refrigerant gas in two stages at both ends thereof, the inner and outer sides of the driving shaft are coupled to each other at predetermined intervals. In the thrust bearing of the turbocompressor which is interposed so that a bearing surface may be formed between a support plate and the inner outer support plate, and is comprised by the fixed plate integrated with the inner peripheral surface of a hermetic container; Gas grooves are formed on both side surfaces of the fixed plate to facilitate the inflow of gas into the bearing surfaces between the inner and outer support plates and the fixed plate, and on the opposite surfaces of the inner and outer support plates opposite to both sides of the fixed plate, Thrust bearing structure of a turbocompressor, characterized in that the coating surface is formed to minimize the frictional loss upon contact. The thrust bearing structure of a turbocompressor according to claim 1, wherein the coating surface is mainly composed of an aluminum oxide film.

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