Information
-
Patent Grant
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6648616
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Patent Number
6,648,616
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Date Filed
Friday, January 4, 200222 years ago
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Date Issued
Tuesday, November 18, 200320 years ago
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Inventors
-
Original Assignees
-
Examiners
- Tyler; Cheryl J.
- Rodriquez; William H.
Agents
-
CPC
-
US Classifications
Field of Search
US
- 417 4105
- 417 42314
- 417 572
- 417 902
- 418 551
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International Classifications
-
Abstract
A sealed compressor assembly includes a compressor pump driven by a motor mounted within a sealed housing. The sealed housing comprises a center shell extending between first and second ends and a lower shell attached to the center shell. The lower shell is generally square shaped with mounting feet extending diagonally from each corner. The lower shell includes a predetermined amount of material removed to shift the resonance frequency of the sealed housing outside the operating frequency range of the motor and compressor.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to sealed compressor housing and specifically to a sealed compressor housing including vibration dampening features to reduce audible noise emission.
Refrigerant compressors typically include a compressor pump unit driven by a motor within a sealed housing. In such compressors, refrigerant flows over the motor driving the compressor pump to cool the motor during operation. Therefore, the sealed housing must provide a fluid tight seal. Most housings are constructed from upper and lower shells attached to corresponding ends of a center cylindrical shell. The motor and compressor are secured within the center shell.
A scroll compressor is one common type of compressor used for commercial and residential applications. Scroll compressors operate by trapping refrigerant within compression chambers formed between interfitting scrolls. Each scroll has a generally spiral wrap extending from a base. Typically, one of the scrolls is an orbiting scroll and the other is non-orbiting. The motor drives the orbiting scroll relative to the non-orbiting scroll to progressively reduce the volume of the compression chambers, thereby compressing the refrigerant.
The compressor and motor create undesirable vibrations and noise. Typically, the motor and compressor operate at a constant speed to emit noise within a known operating frequency range. Noise emanating from the motor and compressor resonates within the sealed housing, thereby increasing the magnitude of noise. Many sealed housings are constructed such that a resonance frequency of the sealed housing is within the operating frequency range of the motor and compressor. The configuration and materials used to construct the sealed housing determines the resonant frequency, and when a sealed housing is constructed such that the resonance frequency is within the frequency range of the motor and compressor, the sealed housing amplifies noise emanating from the motor and compressor.
It is known in the art to modify the construction of the sealed housing to minimize the amplification effects of the sealed housing. Typically, such sealed housings include asymmetrically orientated surfaces disposed within the sealed housing that reflect overall sound waves in a manner to prevent subsequent sound waves from building upon each other to increase noise emanating from the sealed compressor. The asymmetrical shape prevents sound waves from reflecting between two facing surfaces of the sealed housing to minimize resonance within the sealed housing. Asymmetrically shaped components for a sealed compressor increase manufacture and assembly costs to outweigh any noise improvements.
For this reason, it is desirable to design a sealed compressor housing with features that minimize the resonance effects of the compressor and motor to reduce noise emission without prohibitively increasing cost and complicating assembly.
SUMMARY OF THE INVENTION
An embodiment of this invention is a sealed compressor housing with features that attenuate resonant effects of the sealed housing to reduce noise emission.
The disclosed sealed compressor of this invention includes a scroll compressor driven by a motor mounted within a sealed housing. The sealed housing includes a center shell section extending between first and second ends and upper and lower shells attached at the first and second ends. The lower shell has a generally square shaped outer periphery with four mounting feet extending diagonally from each of the corners. The lower shell has a predetermined amount of material removed for attenuating vibrations and noise within an operating frequency range of the compressor assembly. The removal of material within the lower shell affects the resonance frequency at which the sealed housing amplifies noise from the motor and the compressor. In one embodiment, material is removed from the skirt width to make it smaller. The width of the skirt relative to the lower shell shifts the resonance frequency of the sealed housing outside the operating frequency range of the motor and compressor. Adjustment of the resonance frequency of the lower shell reduces overall sound emission of the compressor assembly at any frequency, but the greatest noise reduction is obtained for frequencies within the operating range of the motor and compressor. In the first embodiment of the lower shell, a skirt width no more than four and preferably no more than three times the thickness of the sheet material used forming the lower shell. This configuration resulted in a noise reduction of between 3-5 decibels. In this embodiment, the thickness of the lower shell is approximately 3.5 mm and the skirt width 10 mm.
In another embodiment of the lower shell, notches provided in the skirt changes the resonance frequency of the lower shell. The notches in this embodiment are preferably cut from the skirt in a length selected to be of a particular proportion relative to the total width of the lower shell. In one embodiment, the notch includes radial cutouts at each end, and the notches are positioned symmetrically on each of the four sides of the lower shell.
In another embodiment of the lower shell, the notches are also arranged on each of the four sides of the lower shell, but are instead arranged asymmetrically about the perimeter of the lower shell. The asymmetric arrangement of the notches increases the magnitude of the resonance frequency required to excite the sealed housing, further attenuating audible noise emitted from the sealed housing.
In still another embodiment of the lower shell, a cutout disposed on the top surface changes the resonance frequency of the sealed housing. In this embodiment, the dampening opening is disposed at each corner of the lower shell near each of the mounting feet.
The noise attenuating features of the lower shell disclosed in the various embodiments of this invention change the rigidity of the lower shell to shift the resonance frequency of the sealed housing away from the frequency at which the motor and compressor operate to reduce audible emissions from the sealed compressor. The reduction of audible emissions is accomplished by the adjustment of features on the lower shell at a low cost and without additional assembly steps.
BRIEF DESCRIPTION OF THE DRAWINGS
The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the currently preferred embodiment. The drawings that accompany the detailed description can be briefly described as follows:
FIG. 1
is a cross-sectional view of a sealed compressor housing;
FIG. 2
is an embodiment of the lower shell of this invention;
FIG. 3
is a perspective view of perspective view of a prior art lower shell;
FIG. 4
is a perspective view of another embodiment of the lower shell
FIG. 5
is a plan view of another embodiment of the lower shell; and
FIG. 6
is a plan view of yet another embodiment of the lower shell.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a sealed compressor assembly is generally indicated at
10
in FIG.
1
. The assembly
10
includes a compressor
12
driven by a motor
14
. The compressor
12
illustrated in
FIG. 1
is a scroll compressor that includes an orbiting scroll
16
and a non-orbiting scroll
18
. Although a scroll compressor is shown, any type of compressor
12
can benefit from the application of this invention.
The compressor
12
and motor
14
are mounted within a sealed compressor housing
20
. The sealed compressor housing
20
is fabricated from a first or center shell section
22
extending between first and second ends
24
,
26
. Attached to the first end
24
of the center shell
22
is an upper shell
28
. A second or lower shell section
30
is attached adjacent the second end
26
of the center shell
22
. Preferably, the upper and lower shells
28
,
30
are welded to the center shell
22
to complete the sealed housing
20
. Preferably, the center shell
22
is generally cylindrical in shape, although other shapes would be within the scope of this invention. The lower shell
30
includes a guide section
32
to align the center shell
22
over the lower shell
30
. Preferably, the guide section
32
has a u-shaped cross-section and an inner diameter
34
of the center shell
22
aligns with the outer diameter
36
of the guide section
32
.
Referring to
FIG. 2
, the lower shell
30
includes a skirt
46
disposed about a perimeter. The skirt
46
is disposed at an angle to extend downwardly from a top surface
44
. A width
48
of the skirt is relative to the thickness of the material
49
determines the rigidity of the lower shell
30
.
In one embodiment, the width
48
of the skirt is no more than four and preferably no more than three times the thickness of the material
49
forming the lower shell
30
. Preferably, the lower shell
30
is generally square shaped with a center section
42
and mounting feet
38
extending from each corner. Each of the mounting feet
38
includes a mounting opening
40
. The square section
42
and the mounting feet share a common top surface
44
.
Referring to the prior art
FIG. 3
, the prior art lower shell
50
includes a skirt
52
having a width
54
that is greater than the width
48
of the lower shell
30
. The width
54
of the prior art lower shell
50
in one embodiment was 16 mm. Referring to
FIG. 2
, in one embodiment, the skirt
46
is 10 mm wide. The thickness of material
49
of the lower shell
30
in both cases was approximately 3.5 mm. Reduction of the skirt width from 16 mm in the prior art, to no more than four times the thickness of the lower shell resulted in a 3-5 decibel (dBA) reduction in noise emission. The specific dimensions are provided by way of example to illustrate the invention. A worker skilled in the art would understand that the specific dimensions are application specific and that different skirt widths would be required for other lower shell thicknesses and would fall within the scope of this invention.
Referring to
FIG. 4
, another embodiment of the lower shell is generally indicated at
76
and includes a top surface
62
and a skirt
64
disposed at an angle to the top surface
62
. In this embodiment, the skirt
64
defines a notch
66
disposed between mounting feet
68
. The notch
66
changes the resonance frequency at which the sealed housing
20
resonates. The lower shell has a lateral dimension L between the skirts
64
. The notch
66
includes a length
56
that is preferably between one fourth and one half the total length L of the lower shell. The width
56
of the notch
66
is adjusted to shift the resonance frequency of the sealed housing
20
to be outside the operating frequency range of the motor
14
and compressor
12
. Preferably, opposite ends of the notch
66
includes radial cutouts
58
. The radial cutouts
58
include material removed from the top surface
62
.
Each of the notches
66
are symmetrically located about the perimeter of the lower shell
76
. That is each notch
66
is located in the same location along the skirt
64
such that the notches are symmetrical about the perimeter of the lower shell
76
. Such a configuration is only one way of positioning the notches
66
. The symmetrically positioned notches
66
reduce the rigidity of the lower shell
76
to change the resonance frequency of the sealed housing
20
to be outside the operational frequency range of the motor
14
and compressor
12
.
Referring to
FIG. 5
, another embodiment of the lower shell is generally indicated at
80
and includes notches
82
arranged asymmetrically about the perimeter
84
of the lower shell
80
. As in the previous embodiment, the notches
82
include a length
56
that is proportional to the total length L of the lower shell
80
. The width of each notch
82
is preferably between one fourth and one half the total length L of the lower shell. Arrangement of notches
82
asymmetrically about the perimeter of the lower shell
80
also reduces audible emission by increasing the magnitude of noise or sound waves required to excite the sealed housing
20
. The asymmetrical disposition of the notches
82
further attenuates noise by increasing the magnitude of noise or sound waves emanating from the motor
14
and compressor
12
required to excite the sealed housing
20
. Increasing the magnitude required to excite the sealed housing
20
reduces amplification of audible noise resulting in less total noise emission from the compressor assembly
10
.
Referring to
FIG. 6
, another embodiment of a lower shell is disclosed and is generally indicated at
90
. In this embodiment, the lower shell
90
includes at least one cutout
92
to adjust rigidity of the lower shell
90
. The cutout
92
changes the rigidity of the lower shell
90
to change the frequency at which the sealed housing
20
will resonate. The cutout
92
is preferably a slot disposed in this top surface
98
and includes a length
96
proportional to the total length L. The length
96
of the cutout
92
is at least one third and preferably one fourth the total length L of the lower shell
80
. Although a slot shaped dampening opening
92
is shown, it is within the contemplation of this invention to use cutouts of other shapes.
Mounting feet
94
extend along an axis
100
disposed at an angle
102
relative to a side of the lower shell
90
. Preferably, the angle
102
of the axis
100
relative to the side is forty-five degrees. It should be understood that other angles are within the scope of this invention. Preferably, the cutout
92
is positioned such that the length
96
is substantially transverse to axis
100
although it is within the contemplation of this invention to position the cutout
92
at other angles relative to the axis
100
. Further, one skilled in the art would understand that position of the cutout
92
is application dependent and it is within the contemplation of this invention to locate the cutout
92
at different locations along the top surface
98
.
The foregoing description is exemplary and not just a material specification. The invention has been described in an illustrative manner, and should be understood that the terminology used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. The preferred embodiments of this invention have been disclosed, however, one of ordinary skill in the art would recognize that certain modifications are within the scope of this invention. It is understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. For that reason the following claims should be studied to determine the true scope and content of this invention.
Claims
- 1. A sealed compressor assembly comprising:a compressor pump unit and a motor mounted within a sealed housing; said sealed housing comprising a first shell section; and a second shell section attached to said first shell section said second shell section including a top surface and at least one skirt extending downward from said top surface, said skirt comprising a width and a cutout disposed within said width for attenuating vibrations and noise within an operating frequency range of said compressor assembly.
- 2. The assembly of claim 1, wherein said width of said skirt is no more than four times a thickness of the material forming said second shell.
- 3. The assembly of claim 1, wherein said width of said lower skirt is no more than three times a thickness of said lower second shell.
- 4. The assembly of claim 1, wherein said second shell includes a perimeter, and said skirt is disposed about said perimeter and includes at least one notch disposed within said skirt width.
- 5. The assembly of claim 4, wherein said perimeter includes at least one side having a total length, and said notch including a length no more than one half said total length.
- 6. The assembly of claim 5, wherein said perimeter of said second shell includes at least one side having a total length, and said notch including a length no more than one fourth said total length.
- 7. The assembly of claim 5, wherein said notches are disposed symmetrically about said perimeter of said second shell.
- 8. The assembly of claim 5, wherein said notches are disposed asymmetrically about said perimeter of said second shell.
- 9. A sealed compressor assembly comprising:a compressor pump unit and a motor mounted within a sealed housing; said sealed housing comprising a first shell section; and a second shell section formed of sheet material of a thickness, and attached to said first shell section including a top surface and a skirt extending downwardly from said top surface for a width no more than four times said thickness of said second shell.
- 10. The assembly of claim 9, wherein said width is no more than three times said thickness of said second shell.
- 11. A sealed compressor assembly comprising:a compressor pump unit and a motor mounted within a sealed housing; said sealed housing comprising a first shell section; and a second shell attached to said first shell section and including at least one slot for attenuating vibrations and noise within an operating frequency range of said compressor assembly.
- 12. The assembly of claim 11, wherein said second shell includes a top surface, and said slot is disposed within said top surface.
- 13. The assembly of claim 12, wherein said slot includes a length, and said length is no mere than one fourth a total width of said second shell.
- 14. The assembly of claim 12, wherein said slot includes a length and said length is no more than one half a total width of said second shell.
- 15. The assembly of claim 12, wherein said second shell is generally square shaped and includes four corners, each of said four corners includes a mounting opening and said slot.
- 16. A sealed compressor assembly comprising:a compressor pump unit and a motor mounted within a sealed housing, said sealed housing comprising a first shell section; and a second shell comprising a top surface, a skirt disposed at an angle extending downwardly from said top surface, and a cutout disposed within said skirt.
- 17. The assembly of claim 16, wherein said second shell includes a total length and said cutout includes a length no more than one half said total length.
- 18. The assembly of claim 17, wherein said cutout includes a length no more than one fourth said total length.
US Referenced Citations (12)