U.S. patent application number 12/060394 was filed with the patent office on 2011-12-22 for temporary self-lubricating coating for scroll compressor.
Invention is credited to Pierre Ginies, Gael Meldener, Olivier Paillon.
Application Number | 20110311384 12/060394 |
Document ID | / |
Family ID | 39847070 |
Filed Date | 2011-12-22 |
United States Patent
Application |
20110311384 |
Kind Code |
A9 |
Ginies; Pierre ; et
al. |
December 22, 2011 |
TEMPORARY SELF-LUBRICATING COATING FOR SCROLL COMPRESSOR
Abstract
A sealed compressor is provided with a spray lubricant that will
provide lubricant at various bearing surfaces during initial
start-up of the compressor. The lubricant will wear away quickly
after initial run-in, but liquid lubricant will be provided by that
time.
Inventors: |
Ginies; Pierre; (Sathonay
Village, FR) ; Meldener; Gael; (Lyon, FR) ;
Paillon; Olivier; (Tramoyes, FR) |
Prior
Publication: |
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Document Identifier |
Publication Date |
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US 20090191079 A1 |
July 30, 2009 |
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Family ID: |
39847070 |
Appl. No.: |
12/060394 |
Filed: |
April 1, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/IB2008/001318 |
Jan 30, 2008 |
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12060394 |
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Current U.S.
Class: |
418/55.1 ;
184/6.16; 418/83 |
Current CPC
Class: |
F04C 23/008 20130101;
F04C 2230/91 20130101; F04C 29/02 20130101; F04C 18/0215 20130101;
F04C 2270/701 20130101 |
Class at
Publication: |
418/55.1 ;
418/83; 184/6.16 |
International
Class: |
F04C 29/02 20060101
F04C029/02; F01C 1/04 20060101 F01C001/04 |
Claims
1. A compressor comprising: a sealed container; an electric motor
and a compressor pump unit both mounted within said sealed
container; a shaft driven by said electric motor to drive said
compressor pump unit; and a bearing surface formed between said
shaft and at least one other component within said container, and a
lubricant deposited onto at least one of said bearing surface and
said shaft prior to said container being enclosed to provide
lubrication at initial start-up of the compressor.
2. The compressor as set forth in claim 1, wherein said compressor
pump unit is a scroll compressor.
3. The compressor as set forth in claim 1, wherein said bearing
surface includes at least one fixed surface.
4. The compressor as set forth in claim 3, wherein said at least
one fixed surface includes a bearing at a lower end of said shaft,
on a remote end of said electric motor from said compressor pump
unit.
5. The compressor as set forth in claim 3, wherein said at least
one fixed surface includes a crankcase for supporting a portion of
said compressor pump unit.
6. The compressor as set forth in claim 1, wherein said bearing
surface is a moving surface between said shaft and a portion of
said compressor pump unit.
7. The compressor as set forth in claim 6, wherein said compressor
pump unit is a scroll compressor unit, and said bearing surface is
a bearing mounted within a rear face of an orbiting scroll forming
a portion of said compressor pump unit.
8. The compressor as set forth in claim 1, wherein said lubricant
is deposited on said shaft.
9. The compressor as set forth in claim 8, wherein said lubricant
is sprayed onto said shaft.
10. The compressor as set forth in claim 1, wherein said lubricant
is a dry lubricant.
11. The compressor as set forth in claim 10, wherein said dry
lubricant is a polytetrafluoroethylene material.
12. The compressor as set forth in claim 1, wherein said lubricant
is deposited in a layer less than 50 micrometers.
13. The compressor as set forth in claim 12, wherein said layer is
between 5 and 10 micrometers.
14. The compressor as set forth in claim 1, wherein a refrigerant
is charged within said compressor, said refrigerant being one of a
mixture of R32 and R125, and a mixture of R143a and R125, and oil
is deposited in said compressor, said oil being one of an ester oil
or ether oil.
15. A method of providing lubricant for an initial starting of a
compressor comprising: providing an electric motor and a compressor
pump unit to be mounted within a sealed container; providing a
shaft to be driven by said electric motor to drive said compressor
pump unit; depositing a lubricant on surfaces between said shaft
and at least one support surface; and mounting said shaft into said
motor and in said support surface and then closing said sealed
container.
16. The method as set forth in claim 15, wherein said lubricant is
placed on said shaft prior to said shaft being mounted in said
motor.
17. The method as set forth in claim 16, wherein said lubricant is
sprayed onto said shaft.
18. The method as set forth in claim 17, wherein said lubricant is
a dry lubricant.
19. The method as set forth in claim 15, wherein said lubricant is
deposited in a layer less than 50 micrometers.
20. The method as set forth in claim 19, wherein said layer is
between 5 and 10 micrometers.
Description
RELATED APPLICATIONS
[0001] The application claims priority to PCT Application No.
PCT/FR2008/000105, which was filed on Jan. 30, 2008.
BACKGROUND OF THE INVENTION
[0002] This application relates to a temporary coating for a sealed
compressor, to provide lubricant at bearing surfaces for
start-up.
[0003] Refrigerant compressors are typically mounted in a sealed
container. An electric motor is provided in the sealed container
and drives a rotating shaft. The rotating shaft drives a pump unit
to compress the refrigerant.
[0004] One known type of compressor pump unit is a scroll
compressor. In a scroll compressor, the rotating shaft has an
eccentric pin that works in combination with a rotation prevention
mechanism, typically an Oldham coupling, to cause orbiting movement
of an orbiting scroll member. The orbiting scroll member has a base
with a generally spiral wrap extending from the base. The wrap
interfits with a wrap from a non-orbiting scroll member, and
compression chambers are defined between the two wraps. As the
orbiting scroll member orbits, the size of the compression chambers
decreases and an entrapped refrigerant is compressed.
[0005] In scroll compressors, and in other types of compressors, a
liquid lubricant is typically pulled upwardly through passages in
the shaft to lubricate sliding surfaces in the compressor pump
unit. The lubricant serves to lubricate the surfaces, and prevent
wear or other damage to the components sliding or rotating relative
to each other.
[0006] However, at start-up, it may be the case that sufficient
liquid lubricant will not be at those surfaces. Thus, there may
sometimes be damage to the surfaces before the lubricant can reach
the sliding surfaces. This is especially true at initial run-in of
the compressor, when it is initially started.
[0007] In particular, at initial run-in of the compressor, a
problem called "edge loading" can occur, since there is typically
some small misalignment between the rotating shaft and several
bearings that mount the shaft. This misalignment can result in
edges of the bearing contacting the shaft over a limited surface,
rather than providing support over a larger surface area. Seizure
and undue wear of portions of the components can occur, which is
undesirable. This problem is made more acute if there is
insufficient lubricant during the initial run-in.
[0008] Also, modern refrigerants, which may include mixtures of R32
and R125, or a mixture of R143a and R125 can have some undesirable
interaction in compressors utilizing ester oil or ether oil as a
lubricant. In such compressors, the refrigerant which circulates
over the bearing surfaces, can pull the lubricant away from the
bearing surfaces back downwardly into the sump. When this occurs,
there is even less lubricant during the initial start-up.
[0009] It is known in the prior art to provide various types of
bearings having self-lubricating properties. As an example, any
number of prior art patents have proposed utilizing bearings having
impregnated polytetrafluoroethylene ("PTFE") material. In general,
these proposals could be characterized as somewhat complex and
expensive.
[0010] In addition, these bearings do not address the lack of
liquid lubricant at the sliding surfaces at initial start-up of the
compressor.
SUMMARY OF THE INVENTION
[0011] In a disclosed embodiment of this invention, a
self-lubricating material is sprayed onto components that will be
part of the relatively sliding surfaces. The spray only provides
lubricant for a short period of time after initial start-up of the
compressor, however, it is this run-in period which is most
problematic. In a disclosed embodiment, the self-lubricating
material is a dry material. In one proposed embodiment, it is a
PTFE spray material.
[0012] These and other features of the present invention can be
best understood from the following specification and drawings, the
following of which is a brief description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a cross-sectional view through a scroll compressor
incorporating the present invention.
[0014] FIG. 2 shows a shaft from the FIG. 1 compressor.
[0015] FIG. 3A shows a first bearing surface.
[0016] FIG. 3B shows a second bearing surface.
[0017] FIG. 3C shows a third bearing surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] A compressor 20 is shown in FIG. 1 as a scroll compressor.
The scroll compressor has an orbiting scroll member 22, and a
non-orbiting scroll member 24. An electric motor 26 drives a
rotating shaft 28. The components sit within a sealed shell 21. An
oil sump 30 is defined at the bottom of the shell 21. A first
bearing 32 mounts a lower end 34 of the shaft 28. Crankcase 35
includes another bearing 36 supporting an intermediate portion 38
of the shaft 28. An upper bearing 40 is formed within the orbiting
scroll 22, and supports an eccentric pin 42 from the shaft 28.
[0019] As is known, an inlet or suction tube 44 delivers
refrigerant into a chamber 46 surrounding the motor 26. That
refrigerant circulates to cool the motor, and is delivered to
compression chambers between the scroll members 22 and 24. This
refrigerant is allowed to circulate over the bearing surfaces. As
mentioned above, when particular refrigerants such as mixtures of
R32 and R125, or a mixture of R143a and R125 are utilized in a
compressor utilizing ester oil or ether oil as its lubricant, the
problem mentioned above can occur.
[0020] The refrigerant is compressed between the scroll members 22
and 24 and delivered into a discharge chamber 48, and through a
discharge tube 50 to a downstream location, such as to a condenser
in an air conditioning unit.
[0021] As mentioned above, in the prior art, there has sometimes
been a lack of lubricant at sliding surfaces, such as the bearings
40, 36, and 32. This often occurs at initial run-in or start-up of
the compressor.
[0022] FIG. 2 shows a shaft 28 in which a PTFE spray, shown
schematically by box 51, is sprayed onto surfaces 34, 38 and 42.
The shaft 28 can now be mounted within the motor, the shell sealed,
and the compressor charged with refrigerant. At initial start-up of
the compressor, the PTFE coated shaft will provide lubricant.
[0023] The sprayed locations 34, 38 and 42 corresponding to the
locations of the bearings 40, 36, and 32 as shown in FIGS. 3A-3C.
On the other hand, the spray material could be sprayed on the
bearing locations 40, 36, and 32. However, it may be simpler to
spray the self-lubricating material onto the shaft as shown in FIG.
2.
[0024] The spray coating can be applied in a very thin layer, and
may be less than 50 micrometers, and preferably between 5 and 10
micrometers. Such thicknesses are sufficient to fill up any
microscopic grooves on the shaft surface. Any wear during run-in to
accommodate misalignment will occur in parallel with the removal of
the sprayed layer, but while the sprayed layer will prevent undue
wear and seizure of the bearing material.
[0025] While any number of self-lubricating material may be
utilized, a dry self-lubricating material is preferred. The dry
material will not fall back downwardly into the oil sump, even if
the compressor is shipped and stored for long periods of time, and
will not interact with the above mentioned particular refrigerants.
Even more preferably, a polytetrafluoroethylene material, typically
known as Teflon.RTM. may be utilized. One potential material is
available under the trade name Lubrifiant A Sec, from Ront
Production. See www.ront.com. However, other materials may be
utilized. While spray materials are disclosed, other methods of
depositing the layer can be used.
[0026] While embodiments of this invention have been disclosed, a
worker of ordinary skill in this art would recognize that certain
modifications would come within the scope of this invention. For
that reason, the following claims should be studied to determine
the true scope and content of this invention.
* * * * *
References