U.S. patent application number 13/386829 was filed with the patent office on 2012-07-26 for hermetic compressor.
Invention is credited to Manfred Krueger, Dietmar Erich Bernhard Lilie, Rodrigo Antonio Santiago.
Application Number | 20120189437 13/386829 |
Document ID | / |
Family ID | 43063437 |
Filed Date | 2012-07-26 |
United States Patent
Application |
20120189437 |
Kind Code |
A1 |
Lilie; Dietmar Erich Bernhard ;
et al. |
July 26, 2012 |
HERMETIC COMPRESSOR
Abstract
The present invention refers to a hermetic compressor and, more
specifically, a hermetic compressor comprising a centrifugal pump
(1) to provide oil for the moving parts of said compressor. In the
compressor of the present invention, the vertical shaft (7) extends
axially from the rotor to form a free end (8) in its inferior
portion, and said free end (8) is sized to be received in a
corresponding end (12) of the centrifugal pump (1).
Inventors: |
Lilie; Dietmar Erich Bernhard;
(Joinville, BR) ; Krueger; Manfred; (Joinville,
BR) ; Santiago; Rodrigo Antonio; (Joinville,
BR) |
Family ID: |
43063437 |
Appl. No.: |
13/386829 |
Filed: |
July 26, 2010 |
PCT Filed: |
July 26, 2010 |
PCT NO: |
PCT/BR2010/000257 |
371 Date: |
April 9, 2012 |
Current U.S.
Class: |
415/182.1 |
Current CPC
Class: |
F04B 39/0253
20130101 |
Class at
Publication: |
415/182.1 |
International
Class: |
F01D 25/24 20060101
F01D025/24 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2009 |
BR |
PI0902430-1 |
Claims
1. A hermetic compressor comprising a shell (5) which involves the
component parts of the compressor, an oil reservoir (4) in the
inferior part of the shell, a block cylinder incorporating a
bearing to support a vertical shaft (7) on which a rotor (2) is
assembled, and a centrifugal pump (1) that leads the oil to the
moving parts 5 of the compressor, characterized in that said
vertical shaft extends axially from the rotor (2) to form a free
end (8) in its inferior portion, said free end being sized to be
received in a corresponding end (12) of the centrifugal pump (1),
and at least one portion of the inner sidewall of the end of the
pump and at least one portion of the outer sidewall portion of the
shaft assuming a 10 juxtaposed condition after the reception.
2. A hermetic compressor, in accordance with claim 1, characterized
in that the free end (8) of the vertical shaft (7) extends axially,
and only enough, to enable the attachment of the end of the
pump.
3. A hermetic compressor, in accordance with claim 2, characterized
in that 15 the free end (8) of the vertical shaft (7) extends up to
a maximum of 6 mm.
4. A hermetic compressor, in accordance with claim 1, characterized
in that the free end (8) presents a machined portion having a
reduced external diameter.
5. A hermetic compressor, in accordance with claim 1, characterized
in that the assembly between the free end (8) of the shaft and the
corresponding end (12) of the pump (1) is carried out by
interference fit.
6. A hermetic compressor, in accordance with claim 1, characterized
in that the assembly between the free end (8) of the shaft and the
corresponding end (12) of the pump (1) is carried out by binding.
Description
FIELD OF THE INVENTION
[0001] The present invention refers to a hermetic compressor and,
more specifically, to a hermetic compressor comprising a
centrifugal pump to provide oil for the moving parts of said
compressor.
BACKGROUND OF THE INVENTION
[0002] A compressor has the function of elevating the pressure of a
certain volume of fluid to a pressure that is required to carry out
a determined work. The Refrigeration Industry commonly utilizes
hermetic compressors comprising, in general, a sealed shell which
defines, in its interior, an oil reservoir and an oil pump device
that is responsible for leading the oil of the reservoir to the
moving parts of the compressor.
[0003] The Refrigeration Industry worries about the performance of
the refrigeration compressors. In fact, several studies were
carried out in order to improve such performance, wherein the
latest generation of compressors utilizes variable speed drives.
Upon varying the operational speed of the compressor, the
capability of refrigerating can be set to the demand of the system,
promoting a great benefit in energy consumption.
[0004] A difficulty that results from the reduction of operational
rotation is the pumping of the oil. Pumps normally used in those
compressors are based on the centrifugal effect to lead the oil
towards the parts to be lubricated. Those pumps are widely used due
to its low cost and high reliability. Other alternatives with
different principles can make the pumping in low rotation speeds
possible, but the cost and the reliability are not competitive.
[0005] The prior art oil pumps comprise an oil intake tube having
an oil input. The intake stage depends on the centrifugal effect,
wherein the pump rotation speed forces the oil that goes into the
orifice against the walls of the tube, promoting the increase in
pressure, and, consequently, its elevation.
[0006] Thus, the pumping energy, that is necessary for lubricating,
is obtained from the rotation and from the diameter of the pump. As
a lower rotation is defined for the compressor to achieve a better
performance of the same, which is applied to the refrigeration
system, such rotation tends to be as low as possible, wherein the
oil pump is the main limiting factor to decrease the rotation.
[0007] Three main factors affect the efficiency of the pump: the
diameter of the oil input orifice, the upsetting height (i.e.
height between the suction point of the pump and the highest
elevation point of the oil) and the radius or diameter of the
pump.
[0008] With reference to the first factor, the diameter of the
input orifice of the pump creates a pressure equalization region,
rendering such region inactive. The increase in pressure, which is
resulted from the centrifugation, only occurs in regions having a
higher diameter than the one of the input orifice. Thus, an input
orifice having a very big diameter will prejudice the performance
of the pump in low rotation speeds.
[0009] Regarding the second factor, it shall be noted that the
higher the upsetting height, the greater the energy necessary for
pumping, since the oil shall be elevated up to the input orifice of
the first bearing of the compressor. Subsequently, the propeller of
the shaft will do the remaining pumping work.
[0010] With respect to the third factor, it shall be noted that the
radius or diameter of the pump in the oil output region (i.e., in
the region of the input orifice of the first bearing of the
compressor) is fundamental to the efficiency of the pump. This is
due to the fact that the path followed by the oil through the shaft
interior up to such output orifice shall consider the parabolic
form acquired by the oil from its centrifugation, wherein no
protuberance can intercept such parabola (if an interception
occurs, the flux of oil will be simply interrupted).
[0011] In view of the foregoing, the design of the pump has an
important role in the performance of the compressor, further
considering the need of a pump that is suitable for a compressor
operating at a reduced rotation.
OBJECTIVES OF THE INVENTION
[0012] Thus, one of the objectives of the invention is the
provision of an efficient oil pump for being utilized with a
hermetic compressor having a variable speed driver.
[0013] Another objective of the present invention is the provision
of an oil pump designed to efficiently actuate in a compressor
operating at a reduced rotation.
SUMMARY OF THE INVENTION
[0014] The present invention achieves the above-mentioned
objectives by means of a hermetic compressor comprising a shell
which involves the component parts of a compressor, an oil
reservoir in the inferior part of the shell, a cylinder block that
incorporates a bearing to support a vertical shaft on which a rotor
is assembled, and a centrifugal pump that leads the oil to the
moving parts of the compressor, wherein said vertical shaft extends
axially from the rotor to form a free end in its inferior portion,
the free end being sized to be received in a corresponding end of
the centrifugal pump, and at least one portion of the inner
sidewall of the end of the pump and at least one portion of the
outer sidewall portion of the shaft assuming a juxtaposed condition
after the reception.
[0015] In order to avoid the unnecessary use of raw material, the
free end of the vertical shaft extends axially, and only enough, to
enable the attachment of the end of the pump, wherein, in a
preferred embodiment, the free end of such vertical shaft extends
up to a maximum of 6 mm.
[0016] Furthermore, in said preferred embodiment of the present
invention, the free end presents a machined portion having a
reduced external diameter in order to facilitate the assembly of
the end of the pump.
[0017] The assembly between the free end of the shaft and the
corresponding end of the pump is preferably effectuated by
interference fit, but alternative means, such as binding, would be
equally used.
CONCISE DESCRIPTION OF THE DRAWINGS
[0018] The figures show:
[0019] FIG. 1--FIG. 1 illustrates a cut view of a conventional
hermitic compressor comprising a pumping solution that is already
known in the prior art;
[0020] FIG. 2--FIG. 2 illustrates a cut view of a conventional
hermetic compressor comprising another pumping solution that is
already known in the prior art;
[0021] FIG. 3--FIG. 3 illustrates a cut view of a hermetic
compressor comprising the pumping solution provided by the present
application;
[0022] FIG. 4--FIG. 4 illustrates a detailed cut view of the oil
pump of the present invention, which is assembled on the compressor
shaft.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention will be described below, in a detailed
manner, with basis on the examples of execution that are
represented by the drawings. Although the detailed description
utilizes, as an example, an alternative compressor for
refrigeration, it shall be understood that the principles of the
present invention can be applied to any type, size or configuration
of hermetic compressor.
[0024] FIGS. 1 and 2 illustrate compressors comprising pumping
solutions that are already in the prior art.
[0025] In the solution illustrated in FIG. 1, the oil pump (1) is
inserted in the rotor of the engine (2). The pump (1) has an end
(3) plunged in the oil (4) disposed in a reservoir of the shell (5)
and another end (6) inserted in the rotor (2). This configuration
creates a free pathway for the oil, but restricts the region that
is available for attaching the shaft (7) and the pump. In fact, as
shown in such figure, the shaft (7) is continuous up to the
superior end (6) of the pump.
[0026] In the solution illustrated in FIG. 2, the pump (1) is
inserted in the shaft (7), wherein said shaft (7) extends up to the
end of the rotor (2). This configuration improves the region that
is available for attaching the shaft (7), but the diameter of the
oil passage is affected to enable the insertion of the pump in the
shaft.
[0027] The solution adopted by the present invention is illustrated
in FIGS. 3 and 4. As can be noted upon reading the detailed
description of such figures, the present invention discloses a
pumping solution capable of guaranteeing a suitable diameter for
passing the oil, an optimization of the upsetting height, and a
simplified assembly means for the oil pump.
[0028] Thus, in the compressor of the present invention which is
illustrated in FIG. 3, the shaft (7) extends slightly from the
rotor (2), leaving a free end (8) to enable the assembly of the
centrifugal pump (1).
[0029] It shall be emphasized that the free end (8) has only a
necessary extension for enabling the assembly of the pump (1). This
is due to the need of non-extending too far the shaft (8), what
would result in an unnecessary use of the material, elevating,
therefore, the final cost of the compressor. Thus, in a preferred
embodiment of the present invention, the extension of the free end
is limited to 6 mm.
[0030] As better illustrated in FIG. 4, one end of the pump (1) is
plunged in the oil (4), wherein such end further comprises an input
orifice (9) in its more extreme portion. The other end (12) of the
pump (1) is sized to be connected with the free end (8) of the
shaft (7), wherein the outer side wall of the shaft and the inner
side wall of the pump are arranged in a juxtaposed condition after
fitting.
[0031] In the preferred embodiment of the present invention, one
part of the free end of the shaft (7) is machined to reduce its
external diameter, wherein such machined part is reserved for
receiving the end of the pump to be assembled.
[0032] Additionally, in the preferred embodiment of the present
invention, the assembly of the pump (1) on the free end (8) of the
shaft (7) is carried out by interference fit, not being necessary
the use of binders or adhesives.
[0033] However, it shall be noted that other forms of fitting and
assembling could be utilized. Thus, in an alternative embodiment of
the present invention, the assembly of the pump (1) on the free end
(8) of the shaft (7) is carried out by means of binding. During the
rotation of the pump (1), the centrifugal power causes the
elevation of oil in the inner side wall of both pump and shaft in a
parabolic configuration, as shown by number (10) in FIG. 4. The
pumping energy shall be sufficient so as the upsetting height
reaches the output orifice where the first bearing is disposed, as
shown by number (11) in such figure. The correct sizing of the
parabolic column up to a height H depends on guaranteeing a
sufficient radius R.
[0034] In the present invention, the assembly of the pump (1) in an
external position in relation to both shaft and rotor guarantees a
suitable upsetting height, wherein the input orifice is naturally
disposed closer to the shaft.
[0035] In fact, as the assembly of the pump (1) does not take any
internal extension of the shaft (7) in relation to the rotor, all
interference region of the shaft is available, and the inferior end
of the bearing (13) can be brought very close to the oil (see FIG.
3), in such a way that the orifice (11) can be arranged in a
upsetting height H that is easily reached even at low rotation.
[0036] Furthermore, as previously mentioned, once the pump (1) is
externally assembled in relation to the shaft, it can be guaranteed
a suitable radius R for enabling the parabolic pathway of the oil
up to this reduced upsetting height.
[0037] The configuration for assembling the pump of the present
invention achieves, by means of a simple and economic construction,
a pumping solution that is efficient at providing a compressor
operating at low rotation.
[0038] It shall be understood that the description provided with
basis on the above-mentioned figures only refers to feasible
embodiments for the hermetic cylinder of the present invention. The
scope of the object of the present invention is defined in the
appended claims.
* * * * *