EP2330301A1

EP2330301A1 - Sealed fluid machine producing method and sealed fluid machine

Info

Publication number: EP2330301A1
Application number: EP10758508A
Authority: EP
Inventors: Yoshiyuki Kimata; Hajime Sato
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Thermal Systems Ltd
Priority date: 2009-03-31
Filing date: 2010-03-25
Publication date: 2011-06-08
Anticipated expiration: 2030-03-25
Also published as: JP5535511B2; JP2010236488A; EP2330301A4; EP2330301B1; WO2010113735A1

Abstract

It relates to a sealed fluid machine manufacturing method and a sealed fluid machine with which it is possible to reduce/prevent shifting of a shaft center and to precisely assemble multiple sets of fluid machines to achieve higher performance thereof, even if the shaft length of a rotation shaft is large. A sealed fluid machine manufacturing method (1) in which multiple sets of fluid machines (20, 30) are securely installed, via support members (22, 31), in a sealed container (2) and are separated from each other with a predetermined gap, wherein a gap between the support member (22) of the first fluid machine (20), which is one of the multiple sets of the fluid machines (20, 30), and an inner circumference of the sealed container (2), defined as (S1), and a gap between the support member (31) of the second fluid machine (30) and an inner circumference of the sealed container (2), defined as S2, are set to be S1 > S2, and the multiple sets of fluid machines (20, 30) are assembled by securely installing, first, the support member (31) of the second fluid machine (30) for which the gap (S2) is made small, in the sealed container (2), and then by securely installing the support member (22) of the first fluid machine (20) for which the gap (S1) is made large in the sealed container (2).

Description

{Technical Field}

The present invention relates to a sealed fluid machine manufacturing method and to a sealed fluid machine in which multiple sets of fluid machines that are linked via a common rotation shaft are installed in a sealed container, being secured therein via support members.

{Background Art}

Known sealed fluid machines in which multiple sets of fluid machines are installed in a sealed container, being secured therein, include multi-stage expanders in which individual fluid machines in multiple sets thereof are configured as expanders, expander-integrated compressors in which individual fluid machines are configured as expanders and compressors, multi-stage compressors in which individual fluid machines are configured as lower-stage compressors and higher-stage compressors, multi-cylinder compressors in which individual fluid machines are configured as compressors, and so on. These sealed fluid machines typically have a configuration in which multiple sets of fluid machines (expanders, compressors, and so on) are installed inside a sealed container at the top and bottom thereof, being secured thereto and separated from each other with a predetermined gap, and in which an electric motor is provided between the fluid machines to connect them with each other via a common rotation shaft that is linked to a rotor of the electric motor (for example, see Patent Citations 1 to 3).
With regard to securing individual fluid machines to a sealed container in the sealed fluid machines described above, a typically employed method is such that constituent members of the individual fluid machines, including bearing members, support members, such as cylinder members, and so on, are installed in the sealed container on its inner circumference at multiple locations (for example, three to four locations), being secured thereat from an outer-circumference side with welding (plug welding) or caulking.

{Citation List}

{Patent Literature}

{PTL 1}
Japanese Unexamined Patent Application, Publication No. 2008-163894 (See Fig. 2).
{PTL 2}
Japanese Unexamined Patent Application, Publication No. 2008-163938 (See Fig. 2).
{PTL 3}
Japanese Unexamined Patent Application, Publication No. 2009-19591 (See Fig. 1).

{Summary of Invention}

{Technical Problem}

However, in the above-described sealed fluid machines, because two or more sets of the fluid machines are provided in the sealed container and separated from each other with a predetermined gap, there is a problem in that the shaft length of the rotation shaft that is connected therebetween is large, thereby making it prone to shifting of the shaft center. In particular, in those in which multiple sets of fluid machines are installed in the sealed container and secured thereto with welding (plug welding) or caulking, shifting of the shaft center tends to become considerable due to thermal distortion during welding or distortion during caulking. Therefore, there is a problem in that the assembly precision decreases, which also affects the performance of the individual fluid machines.
The present invention has been conceived in light of the above-described circumstances, and an object thereof is to provide a sealed fluid machine manufacturing method and a sealed fluid machine with which it is possible to reduce or prevent a shift in a shaft center even if the shaft length of a rotation shaft is large, thereby making it possible to precisely assemble multiple sets of fluid machines to achieve higher performance thereof.

{Solution to Problem}

In order to solve the above-described problems, a sealed fluid machine manufacturing method and a sealed fluid machine of the present invention employ the following solutions.
That is, a sealed fluid machine manufacturing method according to a first aspect of the present invention is a sealed fluid machine manufacturing method in which multiple set of fluid machines are securely installed, via a support member by welding or caulking, in a sealed container and are separated from other with a predetermined gap and in which the individual fluid machines are linked via a common rotation shaft, wherein a gap between the support member of a first fluid machine, which is one of the multiple sets of fluid machines, and an inner circumference of the sealed container, defined as S1, and a gap between the support member of a second fluid machine, which is another one of the multiple sets of fluid machines, and an inner circumference of the sealed container, defined as S2, are set to be S1 > S2, and the multiple sets of the fluid machines are assembled by, first, securely installing the support member of the second fluid machine for which the gap S2 is made small in the sealed container, and then by securely installing the support member of the first fluid machine for which the gap S1 is made large in the sealed container.
With the first aspect of the present invention described above, in which the first fluid machine is one of the multiple sets of fluid machines and the second fluid machine is another one of them that are securely installed in the sealed container by the plug welding or caulking, and are separated from each other with the predetermined gap, the gap between the support member of the first fluid machine and the inner circumference of the sealed container, defined as S1, and the gap between the support member of the second fluid machine and the inner circumference of the sealed container, defined as S2, are set to be S1 > S2, and the multiple sets of the fluid machines are assembled by securely installing, first, the support member of the second fluid machine for which the gap S1 is made small in the sealed container and then by securely installing the support member of the first fluid machine for which the gap S1 is made large in the sealed container; therefore, even if the shaft length of the common rotation shaft that links the multiple sets of the fluid machines is large, after the support member of the second fluid machine for which the gap S2 between the support member and the inner circumference of the sealed container is made small is securely installed in the sealed container first, the support member of the first fluid machine for which the gap S1 between the support member and the inner circumference of the sealed container is made large can be securely installed in the sealed container while adjusting the shaft center by using the large gap S1. Accordingly, it is possible to reduce or prevent shifting of the shaft center of the rotation shaft whose shaft length is large, thereby making it possible to precisely assemble the multiple sets of the fluid machines to achieve higher performance thereof.
In addition, in the sealed fluid machine manufacturing method according to the first aspect described above, the above-described sealed fluid machine manufacturing method may be such that an electric motor is securely installed between the multiple sets of fluid machines that are securely installed in the sealed container, and then the multiple sets of the fluid machines are assembled by securely installing the first fluid machine on one side and the second fluid machine on the other side, with the electric motor interposed therebetween.
With the first aspect described above, the multiple sets of the fluid machines are assembled by, after the electric motor is securely installed between the multiple sets of the fluid machines that are securely installed in the sealed container, securely installing the first fluid machine on one side of the electric motor and securely installing the second fluid machine on the other side thereof, with the electric motor interposed therebetween; therefore, even for the sealed fluid machine in which the electric motor is installed between the multiple sets of fluid machines and the multiple sets of fluid machines can be driven by the electric motor via the common rotation shaft, it is possible to secure the support members of the first and second fluid machines in the sealed container by individually adjusting the shaft centers thereof. Therefore, by providing the electric motor between the multiple sets of the fluid machines, shifting of shaft center of the rotation shaft whose shaft length is large can be reduced or prevented, thereby making it possible to precisely assemble the multiple sets of the fluid machines.
Furthermore, in the sealed fluid machine manufacturing method with the above-described configuration, a rotary fluid machine may be employed as the first fluid machine that is installed on one side of the electric motor, and a top-portion bearing may be employed as the support member that securely installs the rotary fluid machine in the sealed container.
With the sealed fluid machine manufacturing method having the above-described configuration, a rotary fluid machine is employed as the first fluid machine that is installed on one side of the electric meter and the top-portion is employed as the support member that securely install the rotary fluid machine in the sealed container; therefore, as compared with one in which the rotary fluid machine is secured to the sealed container with the cylinder the distance the that the rotary fluid its the first, fluid and the support member that the second fluid can be reduced. Accordingly, it is possible to improve coupling alignment the two support members, thereby further improving the assembly of the multiple sets of the fluid machines.
Additionally, a sealed fluid machine according to a second of the present invention is a sealed fluid in which sets of fluid machines are securely installed, via a support member by welding or caulking, in a sealed container and are separated from each other with a predetermined gap, and in which the individual fluid machines are linked via a common rotation shaft, wherein a gap between the support member of a first machine, which is one of the multiple sets of fluid machines, and an inner circumference of the sealed container, defined as S1, and a gap the support member of a second fluid machine, which is another one of the sets of fluid machines, and an inner circumference of the container, defined as S2, are set to be S1 > S2.
With the second of the invention described above, in which the first fluid machines is one of the multiple sets of the fluid machines and the second fluid machine, is another one of them that are securely in the container by the plug or caulking, from other with the predetermined gap, the gap the support of the first fluid and the inner circumference of the container, as S1, and the gap the support of the second fluid and the inner of the sealed container, defined as S2, are set to be S1 > S2; therefore, even if the shaft length of the common rotation shaft that links the multiple sets of the fluid its it is possible to securely install the support member of the first fluid machine in the sealed container while the shaft center using the gap S1 by securely installing, first, the support of the second fluid machine for the gap S2 the support and the inner circumference of the sealed container is made small in the sealed and then by securely installing the first fluid for the gap S1 between the support and the inner circumference of the sealed its made in the sealed container. Accordingly, it is possible to or prevent shifting of the shaft center of the rotation shaft whose shaft length is large, thereby making it possible to precisely assemble the multiple sets of the fluid machines to achieve higher performance thereof.
Furthermore, in the sealed fluid machine of the second aspect described above, an electric motor may be securely installed between the multiple sets of fluid machines that are securely installed in the sealed container and are separated from each other with a predetermined gap, the first fluid machine is securely installed on one side of the electric motor, and the second fluid machine is installed on the other side thereof, with the electric motor interposed therebetween.
With the above-described second aspect, the electric motor is securely installed between the multiple sets of the fluid machines that are securely installed in the sealed container and separated from each other with the predetermined gap, and the first fluid machine is securely installed on one side of the electric motor and the second fluid machine is securely installed on the other side thereof, with the electric motor interposed therebetween; therefore, even for a fluid machine in which the electric motor is installed between the multiple sets of the fluid machines, thereby making it possible to drive the multiple sets of the fluid machines by the electric motor via the common rotation shaft, it is possible to secure the support members of the first and second fluid machines in the sealed container by individually adjusting their shaft centers. Accordingly, by providing the electric motor between the multiple sets of the fluid machines, it is possible to reduce or prevent shifting of the shaft center of the rotation shaft whose shaft length is large, thereby making it possible to precisely assemble the multiple sets of the fluid machines.
In addition, in the configuration of the sealed fluid machine of the second aspect described above, a multi-stage compressor may be formed in which a lower-stage compressor is employed as the first fluid machine and a higher-stage compressor is employed as the second fluid machine, and in which intermediate-pressure gas that is ejected into the sealed container by being compressed by the lower-stage compressor is taken into the higher-stage compressor to be compressed to high pressure.
With the above-described second aspect, a lower-stage compressor is employed as the first fluid machine and a higher-stage compressor is employed as the second fluid machine and the intermediate gas ejected into the sealed container by being compressed by the lower-stage compressor is taken into the higher-stage compressor to be compressed to a high pressure; therefore, even in a multi-stage compressor in which the multiple sets of lower-stage compressors and higher-stage compressors are driven via the common rotation shaft and the shaft length thereof is large, the support members of the lower-stage compressor and the higher-stage compressor can be securely installed in the sealed container by adjusting their shaft centers. Accordingly, it is possible to reduce or prevent shifting of the shaft center of the common rotation shaft whose shaft length is large, thereby making it possible to precisely assemble the multiple sets of lower-stage and higher-stage compressors to achieve higher performance in the multi-stage compressor.
Furthermore, in the sealed fluid machine with the above-described configuration, a rotary compressor may be employed as the lower-stage compressor, and a scroll compressor may be employed as the higher-stage compressor.
With the sealed fluid machine with the above-described configuration, because a rotary compressor is employed as the lower-stage compressor and a scroll compressor is employed as the higher-stage compressor, the intermediate-pressure gas ejected into the sealed container by being compressed by the lower-stage rotary compressor can be taken into the higher-stage scroll compressor to be compressed to a high pressure. Accordingly, it is possible to obtain a compact, high-performance multi-stage compressor in which shortcomings of the rotary compressor and the scroll compressor are compensated for.
Additionally, in the sealed fluid machine with the above-described configuration, a top-portion bearing of the rotary compressor may be employed as the support member for securely installing the rotary compressor in the sealed container.
With the sealed fluid machine with the configuration, because the top-bearing of the rotary compressor is employed as the support member that securely support the rotary compressor in the sealed container, as compared with one in which the rotary compressor is secured to the sealed container with the cylinder member, the inter-support-member distance between the support member that supports the rotary compressor, which is the first fluid machine, and the support member that supports the second fluid machine can be reduced. Therefore, it is possible to improve coupling alignment between the two support members, thereby making it possible to further improve the assembly precision of the multiple sets of the fluid machines.

{Advantageous Effects of Invention}

With the present invention, a first fluid machine, in which a gap S1 between the support member and an inner circumference of a sealed container is made large, can be securely installed inside the sealed container while adjusting a shaft center using the large gap S1, after securely installing in the sealed container a support member of a second fluid machine, in which a gap S2 between the support member and an inner circumference of the sealed container is made small; therefore, even if the shaft length of a common rotation shaft that links multiple sets of fluid machines is large, it is possible to reduce or prevent a shift in the shaft center of the rotation shaft whose shaft length is large, thereby making it possible to precisely assemble the multiple sets of the fluid machines to achieve high performance thereof.

{Brief Description of Drawings}

{Fig. 1} Fig. 1 is a longitudinal sectional view of a sealed fluid machine according to a first embodiment of the present invention.
{Fig. 2} Fig. 2 is a partial enlarged view of the sealed fluid machine shown in Fig. 1.

{Description of Embodiments}

Embodiments according to the present invention will be described below with reference to the drawings.

{First Embodiment}

A first embodiment of the present invention will be described below, using Figs. 1 and 2.
Fig. 1 shows a longitudinal sectional view of a sealed fluid machine 1 according to the first embodiment of the present invention. Here, the sealed fluid machine 1 in which multiple sets of fluid machines are provided inside a sealed container will be described using a sealed multi-stage compressor (sealed fluid machine) 1 as an example. The sealed multi-stage compressor 1 according to this embodiment is provided with a sealed container 2 constituted of a middle housing 3, a top housing 4, and a bottom housing 5. These housings 3, 4, and 5 form the sealed container 2 and are integrated by having the top housing 4 and the bottom housing 5 respectively welded to the top and bottom ends of the middle housing 3 over the entire circumferences thereof. The bottom housing 5 is provided with a plurality of mounting legs 6.
At a central portion of the middle housing 3, an electric motor 7 constituted of a stator 8 and a rotor 9 is securely installed by being pressed into the middle housing 3. The rotor 9 of the electric motor 7 is connected to a common rotation shaft 10 for the multiple sets of fluid machines, which extends in vertical directions so as to be linked at a bottom-end portion thereof to a lower-stage compressor 20 that constitutes a first fluid machine, described below and to be linked at a top-end portion thereof to a higher-stage compressor 30 that constitutes a second fluid machine, described below.
One side (lower side) of the electric motor 7 is provided with the lower-stage compressor (first fluid machine) 20 that constitutes the first fluid machine, which is one of the multiple sets of fluid machines. This lower-stage compressor 20 is configured as a rotary compressor (rolling-piston compressor) constituted of a cylinder member 21 that forms a cylinder chamber, a top-portion bearing 22 and bottom-portion bearing 23 pair disposed at a top surface and a bottom surface of the cylinder member 21, a rotor 24 that is fitted to a crank portion 10A provided at a lower portion of the rotation shaft 10 and that rotates in an inner circumference of the cylinder chamber due to the rotation of the rotation shaft 10, and so on.
The above-described lower-stage compressor (rotary compressor) 20 may be a known unit and is installed in the middle housing 3 at a lower section thereof on an inner circumference at multiple locations, for example three locations, being secured thereat from an outer-circumference side with welding (or caulking) using plug welds 25 via a top-portion bearing 22 that constitutes a support member for the sealed container 2. The lower-stage compressor (rotary compressor) 20 is configured to compress low-pressure refrigerant gas taken in from outside via an intake pipe to an intermediate pressure and then to eject it into the sealed container 2.
In addition, the higher-stage compressor (second fluid machine) 30 that constitutes the second fluid machine, which is another one of the multiple sets of the fluid machines, is provided on the other side (upper side) of the electric motor 7. This higher-stage compressor 30 is configured as a scroll compressor constituted of a bearing member 31, a fixed scroll 32 that is securely installed on the bearing member 31, and an orbiting scroll 33 that is fitted to a crank pin 10B provided at a top end of the rotation shaft 10, that is also engaged with the fixed scroll 32 to form a compression chamber, and that is orbitally driven around the fixed scroll 32 by rotation of the rotation shaft 10, and so on.
The above-described higher-stage compressor (scroll compressor) 30 may be a known unit and is installed in the middle housing 3 at an upper section thereof on an inner circumference at multiple locations, for example three locations, being secured thereat from an outer-circumference side with welding (or caulking) using plug welds 35 via a bearing member 31 that constitutes a support member for the sealed container 2. The higher-stage compressor (scroll compressor) 30 is configured to take in the intermediate-pressure refrigerant gas ejected into the sealed container 2 from the lower-stage compressor (rotary compressor) 20 to compress it to a high pressure and then to eject it into an ejection chamber 36 that is formed as a section in the top housing 4 to send it out to the outside via a discharge cover (not shown), etc.
With the above-described sealed multi-stage compressor (sealed fluid machine) 1, when manufacturing the sealed multi-stage compressor 1 by securely installing the lower-stage compressor (rotary compressor) 20, which is the first fluid machine, and the higher-stage compressor (scroll compressor) 30, which is the second fluid machine, in the sealed container 2 (middle housing 3), in order to reduce or prevent shifting of the shaft center of the rotation shaft 10, which has a large shaft length, as shown in Fig. 2, a gap between the top-portion bearing 22 and the inner circumference of the sealed container 2 (middle housing 3), defined as S1, and a gap between the bearing member 31 and the inner circumference of the sealed container 2 (middle housing 3), defined as S2, are set to be S1 > S2, wherein the top-portion bearing 22 and the bearing member 31 are the support members for the respective portions.
In addition, during manufacturing, first, the bearing member 31 of the higher-stage compressor 30, which is the second fluid machine for which the gap S2 is made small, is installed in the sealed container 2 by securing it thereto with the plug welds 35 (or caulking), and then the top-portion bearing 22 of the lower-stage compressor 20, which is the first fluid machine for which the gap S1 is made large, is installed in the sealed container 2 by securing it thereto with the plug welds 25 (or caulking) while adjusting the shaft center using the large gap S1, so that the higher-stage compressor 30 and the lower-stage compressor 20 are thereby sequentially assembled. Note that, the above-described gaps S1 and S2 are set such that, for example, the smaller gap S2 is about 0.1 mm, and the larger gap S1 is about twice the size of the gap S2.
With the configuration described above, this embodiment affords the following operational advantages.
As described above, the sealed multi-stage compressor (sealed fluid machine) 1 according to this embodiment has a configuration in which the electric motor 7 is installed in the central portion of the sealed container 2, and the lower-stage compressor 20, which is the first fluid machine, and the higher-stage compressor 30, which is the second fluid machine, are provided at both ends thereof; therefore, the shaft length of the rotation shaft 10, which is a shared shaft that links the two, is increased, which makes the shaft center prone to shift and, moreover, this tendency becomes considerable because it is affected by welding or caulking of the top-portion bearing 22 and the bearing member 31, which are the support members.
Therefore, in this embodiment, in which the lower-stage compressor 20, which is one of the multiple sets of the fluid machines, and the higher-stage compressor 30, which is another one of them, are securely installed in the sealed container 2 with the plug welds 25 or 35, or by caulking, separated from each other with a predetermined gap, the gap between the top-portion bearing (support member) 22 of the lower-stage compressor (first fluid machine) 20 and the inner circumference of the sealed container 2, defined as S1, and the gap between the bearing member (support member) 31 of the higher-stage compressor (second fluid machine) 30 and the inner circumference of the sealed container 2, defined as S1, are set to be S1 > S2, so that the lower-stage compressor 20 and the higher-stage compressor 30, which are the multiple sets of the fluid are assembled by, first, installing the bearing member 31 of the higher-stage compressor 30 for which the gap S2 is made small in the sealed container 2 by securing it thereto with the plug welds 35 or caulking, and then by installing the top-portion bearing 22 of the lower-stage compressor 20 for which the gap S1 is made large in the sealed container 2 by securing it thereto with the plug welds 25 or caulking.
Because of this, even if the shaft length of the common rotation shaft that links the lower-stage compressor 20 and the higher-stage compressor 30 is large, the bearing member 31, which is the support member of the higher-stage compressor 30 for which the gap S2 between the inner circumference of the sealed container 2 is made small, is installed first to be secured in the sealed container 2, and then the top-portion bearing 22, which is the support member of the lower-stage compressor 20 for which the gap S1 between the inner circumference of the sealed container 2 is made large, can be installed to be secured in the sealed container 2 while adjusting the shaft center by using the larger gap S1. Accordingly, the shifting of the shaft center of the rotation shaft 10 whose shaft length is large can be reduced or prevented, and the lower-stage compressor 20 and the higher-stage compressor 30, which are the multiple sets of fluid machines, can be precisely assembled, thereby making it possible to achieve higher performance thereof.
In particular, because a rotary compressor is employed as the lower-stage compressor 20, which constitutes the first fluid machine, and because the top-portion bearing 22 is employed as the support member for securely installing this rotary compressor 20 in the sealed container 2, as compared with one in which the rotary compressor 20 is securely installed in the sealed container 2 with the cylinder member 21, it is possible to reduce the inter-support-member distance between the top-portion bearing 22 that supports the lower-stage compressor 20 and the bearing member 31 that supports the higher-stage compressor 30. Accordingly, coupling alignment between the top-portion bearing 22 and the bearing member 31 is improved, thereby making it possible to further improve the assembly precision of the lower-stage compressor 20 and the higher-stage compressor 30, which are the multiple stets of fluid machines.
In addition, the sealed multi-stage compressor (sealed fluid machine) 1 is configured employing the lower-stage compressor 20 as the first fluid machine and the higher-stage compressor 30 as the second fluid machine so that the intermediate-pressure gas which is ejected into the sealed container 2 by being compressed by the lower-stage compressor 20 is taken into the higher-stage compressor 30 to be compressed to high pressure; therefore, even in the sealed multi-stage compressor 1 in which multiple sets of the lower-stage compressors 20 and the higher-stage compressor 30 can be driven via the common rotation shaft 10 whose shaft length is large, shifting of the shaft center of the common rotation shaft 1 can be reduced or prevented, and the lower-stage and the higher- stage compressors 20 and 30 can be precisely assembled, thereby making it possible to achieve higher performance of the sealed multi-stage compressor 1.
Furthermore, because a rotary compressor is employed as the lower-stage compressor 20 and a scroll compressor is employed as the higher-stage compressor 30, it is possible to compress the intermediate gas that is compressed by the lower-stage rotary compressor and that is ejected into the sealed container 2 to a high pressure by taking it into the higher-stage scroll compressor. Accordingly, it is possible to obtain a compact, high-performance sealed multi-stage compressor 1 in which the shortcomings of a rotary compressor, such as an increase in compression leakage during a period of high pressure difference, and so on, and the shortcomings of a scroll compressor, such as an increase in outer diameter resulting from attempting to ensure a high displacement quantity, and so on are compensated for.

{Other Embodiments}

Next, other embodiments of the present invention will be described below.

(1) In the above-described first embodiment, the gap between the top-portion bearing (support member) 22 of the lower-stage compressor 20, which is the first fluid machine, and the inner circumference of the sealed container 2, defined as S1, and the gap between the bearing member (support member) 31 of the higher-stage compressor 30, which is the second fluid machine, and the inner circumference of the sealed container 2, defined as S2, are set to be S1 > S2 so that the bearing member 31 of the higher-stage compressor 30 for which the gap S2 is made small is installed first to be seeured in the sealed container 2 using the plug welds 35 or caulking; however, in contrast to the above description, S1 and S2 may be set to be S1 < S2, and the top-portion bearing 21 of the lower-stage compressor 20 for which the gap S1 is made small may be installed first to be secured in the sealed container 2 by the plug welds 25 or caulking; operational advantages similar to those in the first embodiment can also be obtained in this way.

(2) In the above-described first embodiment, the rotary compressor employed as the lower-stage compressor 20, which is the first fluid machine, can be a multi-cylinder compressor, such as a two-cylinder rotary compressor, or the like.
(3) In the above-described first embodiment, the rotary compressor employed as the lower-stage compressor 20, which is the first fluid machine, is securely installed in the sealed container 2 via the top-portion bearing 22; however, it is not necessary to support it with the top-portion bearing 22, and the rotary compressor employed as the lower-stage compressor 20 may be securely installed in the sealed container 2 using the cylinder member 21 as the support member.

(4) Furthermore, in the above-described first embodiment, as a sealed fluid machine 1, the sealed multi-stage compressor 1 in which the lower-stage compressor 20 is employed as the first fluid machine, which is one of the multiple sets of the fluid machines, and the higher-stage compressor 30 is employed as the second fluid machine, which is another one of them, has been described as an example; however, the first fluid machine and the second fluid machine can be replaced with fluid machines such as other expanders, compressors, and so on, and it is also possible to configure the sealed fluid machine 1 as a multi-stage expander, an expander-integrated compressor, a multi-cylinder compressor, etc.
Note that the present invention is not limited to inventions according to the above-described embodiments, and appropriate modifications are possible within a range that does not depart from the spirit thereof. For example, although the above-described embodiments have illustrated examples in which, with regard to the gaps S1 and S2, the smaller one S2 is set at about 0.1 mm and the larger one S1 is set to about twice the size of S2, this is merely an example, and gap sizes are naturally not limited to such values. In addition, in the above-described embodiments, oil supply structures for the lower-stage compressor 20 and the higher-stage compressor 30 are omitted; however, it is needless to say that known oil supply structures can be employed.

{Reference Signs List}

1 sealed fluid machine (sealed multi-stage compressor)
2 sealed container
7 electric motor
10 rotation shaft
20 lower-stage compressor (first fluid machine)
22 top-portion bearing (support member)
25 plug weld
30 higher-stage compressor (second fluid machine)
31 bearing member (support member)
35 plug weld
S1 gap between top-portion bearing and inner circumference of sealed container
S2 gap between bearing member and inner circumference of sealed container

Claims

A sealed fluid machine manufacturing method in which multiple sets of fluid machines are securely installed, via a support member by welding or caulking, in a sealed container and are separated from each other with a predetermined gap and in which the individual fluid machines are linked via a common rotation shaft,
wherein a gap between the support member of a first fluid machine, which is one of the multiple sets of fluid machines, and an inner circumference of the sealed container, defined as S1, and a gap between the support member of a second fluid machine, which is another one of the multiple sets of fluid machines, and an inner circumference of the sealed container, defined as S2, are set to be S1 > S2, and the multiple sets of the fluid machines are assembled by, first, securely installing the support member of the second fluid machine for which the gap S2 is made small in the sealed container, and then by securely installing the support member of the first fluid machine for which the gap S1 is made large in the sealed container.
A sealed fluid machine manufacturing method according to Claim 1, wherein, an electric motor is securely installed between the multiple sets of fluid machines that are securely installed in the sealed container, and then the multiple sets of the fluid machines are assembled by securely installing the first fluid machine on one side and the second fluid machine on the other side, with the electric motor interposed therebetween.
A sealed fluid machine manufacturing method according to Claim 2, wherein a rotary fluid machine is employed as the first fluid machine that is installed on one side of the electric motor, and a top-portion bearing is employed as the support member that securely installs the rotary fluid machine in the sealed container.
A sealed fluid machine in which multiple sets of fluid machines are securely installed, via a support member by welding or caulking, in a sealed container and are separated from each other with a predetermined gap, and in which the individual fluid machines are linked via a common rotation shaft,
wherein a gap between the support member of a first fluid machine, which is one of multiply sets of fluid machines, and an inner circumference of the sealed container, defined as S1, and a gap between the support member of a second fluid machine, which is another one of the multiple sets of fluid machines, and an inner circumference of the sealed container, defined as S2, are set to be S1 > S2.
A sealed fluid machine according to Claim 4, wherein an electric motor is securely installed between the multiple sets of fluid machines that are securely installed in the sealed container and are separated from each other with a predetermined gap, the first fluid machine is securely installed on one side of the electric motor, and the second fluid machine is installed on the other side thereof, with the electric motor interposed therebetween.
A sealed fluid machine according to Claim 4 or 5, wherein a multi-stage compressor is formed in which a lower-stage compressor is employed as the first fluid machine and a higher-stage compressor is employed as the second fluid machine, and in which intermediate-pressure gas that is ejected into the sealed container by being compressed by the lower-stage compressor is taken into the higher-stage compressor to be compressed to high pressure.
A sealed fluid machine according to Claim 6, wherein a rotary compressor is employed as the lower-stage compressor, and a scroll compressor is employed as the higher-stage compressor.
A sealed fluid machine according to Claim 7, wherein a top-portion bearing of the rotary compressor is employed as the support member for securely installing the rotary compressor in the sealed container