U.S. patent application number 10/525262 was filed with the patent office on 2006-02-23 for hermetic compressor.
This patent application is currently assigned to MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD. Invention is credited to Ko Inagaki, Yoshinori Ishida, Akira Nakano, Shuhei Sugimoto.
Application Number | 20060039803 10/525262 |
Document ID | / |
Family ID | 34213853 |
Filed Date | 2006-02-23 |
United States Patent
Application |
20060039803 |
Kind Code |
A1 |
Nakano; Akira ; et
al. |
February 23, 2006 |
Hermetic compressor
Abstract
A compressing unit of a hermetic compressor includes a suction
valve placed at an opening of a compressing room and a suction
muffler. The muffler includes a suction muffler body which forms a
sound-deadening space, a first communicating path which
communicates with the suction valve and with the sound-deadening
space, and a second communicating path which communicates with a
hermetic container and with the sound-deadening space. An opening,
situated in the sound-deadening space, of the first communicating
path, and an opening, situated in the sound-deadening space, of the
second communicating path are both open in the same direction. In
addition, a sound-insulating wall is disposed on the wall of the
muffler body at a place at least confronting both of the openings.
This structure achieves low noise and high efficiency.
Inventors: |
Nakano; Akira; (Soraku-gun,
JP) ; Inagaki; Ko; (Fujisawa-shi, JP) ;
Ishida; Yoshinori; (Fujisawa, JP) ; Sugimoto;
Shuhei; (Kusatsu-shi, JP) |
Correspondence
Address: |
ROSSI, KIMMS & McDOWELL LLP.
P.O. BOX 826
ASHBURN
VA
20146-0826
US
|
Assignee: |
MATSUSHITA ELECTRIC INDUSTRIAL CO.,
LTD
1006, OAZA KADOMA
KADOMA-SHI
JP
571-8501
|
Family ID: |
34213853 |
Appl. No.: |
10/525262 |
Filed: |
July 27, 2004 |
PCT Filed: |
July 27, 2004 |
PCT NO: |
PCT/JP04/11012 |
371 Date: |
February 22, 2005 |
Current U.S.
Class: |
417/312 ;
417/415 |
Current CPC
Class: |
F04B 39/0055
20130101 |
Class at
Publication: |
417/312 ;
417/415 |
International
Class: |
F04B 39/00 20060101
F04B039/00; F04B 35/04 20060101 F04B035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 26, 2003 |
JP |
2003-300869 |
Claims
1. A hermetic compressor comprising: an electric motor unit; a
compressing unit driven by the electric motor unit; a hermetic
container accommodating the electric motor unit and the compressing
unit; and the compressing unit comprising: a suction valve disposed
at an opening of a compressing room and a suction muffler having: a
suction muffler body for forming a sound-deadening space; a first
communicating path for communicating with the suction valve and
with the sound-deadening space; and a second communicating path for
communicating with the hermetic container and with the
sound-deadening space, wherein an opening, situated in the
sound-deadening space, of the first communicating path, and an
opening, situated in the sound-deadening space, of the second
communicating path are open in a substantially identical direction,
and wherein a wall of the suction muffler body has a
sound-insulating wall at a place at least confronting both of the
openings situated in the sound-deadening space.
2. The hermetic compressor of claim 1, wherein the sound-insulating
wall is formed of a part of the suction muffler body.
3. The hermetic compressor of claim 2, wherein the sound-insulating
wall and the wall of the suction muffler body form a blocked
space.
4. The hermetic compressor of claim 2, wherein the suction muffler
is made from synthetic resin and formed of at least two components,
and wherein the sound-insulating wall is disposed vertically with
respect to an opening face of the suction muffler body.
5. The hermetic compressor of claim 1, wherein the sound-insulating
wall works as a guiding wall for guiding gas sucked from the second
communicating path to the first communicating path smoothly.
6. The hermetic compressor of claim 5, wherein a sectional view of
the guiding wall shows like letter U.
Description
TECHNICAL FIELD
[0001] The present invention relates to hermetic compressors which
are used in refrigerators, air-conditioners, and refrigerating
plants.
BACKGROUND ART
[0002] In recent years, hermetic compressors used in refrigerating
plants and others have been required to reduce the operating noises
and use energy more efficiently. Japanese Patent Application
Non-Examined Publication No. 2003-42064 discloses one of
conventional hermetic compressors. This hermetic compressor
(hereinafter referred to simply as a compressor) increases
sound-deadening effect of its suction muffler, and utilizes this
sound-deadening effect for increasing an amount of refrigerant
circulating in the compressing room, thereby obtaining a higher
energy efficiency. Another conventional one is disclosed in
Japanese Patent Application Non-Examined Publication No.
H11-303739. This compressor maintains refrigerant gas returned from
the refrigerating cycle at a low temperature and a higher density,
then the refrigerant gas is sucked into a compressing room, thereby
obtaining a higher energy efficiency. The foregoing conventional
compressors are described hereinafter with reference to FIG. 6-FIG.
8. FIG. 6 shows a sectional view of the conventional compressor,
FIG. 7 shows a sectional view of a suction muffler of the
conventional compressor, and FIG. 8 shows flow-rate vectors that
illustrate behavior of refrigerant gas in the suction muffler of
the conventional compressor.
[0003] In FIG. 6, hermetic container 1 includes electric motor unit
5 formed of rotor 4 and stator 3 having winding 2, compressing unit
6 driven by electric motor unit 5, and oil 8 therein.
[0004] A rough structure of compressing unit 6 is described next.
Crankshaft 10 includes main-shaft 11 to which rotor 4 is
press-fitted, and off-center section 12 with respect to main shaft
11. Oil pump 13 is disposed inside main shaft 11 and open in oil 8.
Cylinder block 20 disposed above electric motor unit 5 has
cylindrical compressing room 22 and bearing 23 which rotatably
supports main shaft 11. Piston 30 is inserted into compressing room
22 such that it can reciprocate in compressing room 22, and coupled
to off-center section 12 via coupler 31.
[0005] Valve plate 35 seals an opening of compressing room 22, and
valve plate 35 includes suction hole 38, which can communicate with
compressing room 22 when suction valve 34 opens. Cylinder head 36
is rigidly disposed opposite to compressing room 22 via valve plate
35. Suction pipe 37 is fixed to hermetic container 1 and coupled to
a lower pressure side (not shown) of a refrigerating cycle for
guiding refrigerant gas (not shown) into container 1. Suction
muffler 40 is made of synthetic resin, such as
polybutylene-terephtalate to which glass fiber is added, and
rigidly sandwiched by valve plate 35 and cylinder head 36.
[0006] In FIG. 7, suction muffler 40 has first communicating path
45 and second communicating path 46. To be more specific, suction
muffler 40 includes sound-deadening space 43, and has second
communicating path 46 of which first opening 46b communicates with
hermetic container 1 and second opening 46a opens extending to
sound-deadening space 43. Suction muffler 40 still has first
communicating path 45 of which first opening 45b communicates with
suction hole 38 of valve plate 35 and second opening 45a opens
extending to sound-deadening space 43.
[0007] FIG. 8 shows flow-rate vectors 60 which illustrate behavior
of refrigerant gas in suction muffler 40. The flow-rate vectors are
obtained by computer simulation. Respective vectors show a
magnitude of flow-rate with their lengths, and the directions of
the vectors indicate the flow directions.
[0008] Upper eddy 61 indicated by an arrow mark is formed of upward
flow out of the refrigerant gas sucked from opening 46a of second
communicating path 46. Lower eddy 62 indicated by another arrow
mark is formed of downward flow out of the refrigerant gas sucked
from opening 46a.
[0009] An operation of the foregoing conventional compressor is
demonstrated hereinafter. Rotor 4 of electric motor unit 5 rotates
crankshaft 10, and rotating motion of off-center section 12 is
transferred to piston 30 via coupler 31, so that piston 30
reciprocates in compressing room 22. This mechanism guides
refrigerant gas from the refrigerating system (not shown) through
suction pipe 37 into hermetic container 1. The refrigerant gas
introduced in container 1 is sucked from opening 46b of suction
muffler 40 and discharged from opening 46a of second communicating
path 46 into sound-deadening space 43. The discharged refrigerant
gas collides against the wall of suction muffler 40 at a place
nearest and facing to opening 46a, then form upper eddy 61 and
lower eddy 62, and circulates in sound-deadening space 43. Then the
refrigerant gas of upper eddy 61 is sucked from opening 45a into
first communicating path 45, and guided to suction hole 38 punched
on valve plate 35. When suction valve 34 opens, the refrigerant gas
is sucked into compressing room 22, and compressed by the
reciprocating motion, then discharged to the refrigerating
system.
[0010] When the refrigerant is sucked into compressing room 22, the
refrigerant produces pressure pulsation, which propagates in the
reversal direction to the flow of the refrigerant, i.e. from
opening 45a of first communicating path 45 to sound-deadening space
43. In this case, first communicating path 45 extends into
sound-deadening space 43 having high sound-deadening effect, e.g.
opening 45a is situated at a node of sound of 3-4 kHz band which
causes a noise problem, thereby obtaining high sound-deadening
effect at a specific frequency band.
[0011] The pressure pulsation attenuated in sound-deadening space
43 can be further attenuated if the dimensions of sound-deadening
space 43 as well as the length and inner diameter of second
communicating path 46 are appropriately adjusted, which results in
more effective sound-deadening.
[0012] However, in the foregoing conventional structure, the
refrigerant gas is sucked from the refrigerating system (not show)
into suction muffler 40 via container 1 due to reciprocating motion
of piston 30, then the gas is discharged to sound-deadening space
43 through second communicating path 46. As shown in FIG. 8, the
refrigerant gas does not directly flow into first communicating
path 45, but collides against the wall of suction muffler 40 at
nearest and facing to opening 46a, then forms upper eddy 61 and
lower eddy 62, and circulates in sound-deadening space 43. The
refrigerant gas returned from the refrigerating system is kept at a
low temperature; however, the gas is greatly heated due to heat
exchange with refrigerant gas of a high temperature in hermetic
container 1 via the nearest wall. Further, the circulation flow
formed of upper eddy 61 and lower eddy 62 is heated by the
refrigerant gas remaining in sound-deadening space 43 because the
temperature of this refrigerant gas has risen. Then the circulation
flow is sucked from opening 45a of first communicating path 45 and
flows into compressing room 22. As a result, compressing room 22
reduces mass-flow rate of the refrigerant to be sucked therein, so
that suction efficiency is lowered.
[0013] The refrigerant gas discharged from opening 46a of second
communicating path 46 into sound-deadening space 43 forms upper
eddy 61 and lower eddy 62. Fluid inertia force of the refrigerant
gas sucked into sound-deadening space 43 thus substantially
decreases across sound-deadening space 43 from opening 46a to
opening 45a, and this reduction incurs greater pressure loss. As a
result, the mass flow rate of the refrigerant gas sucked into
compressing room 22 is further lowered, which aggravates the
suction efficiency.
[0014] Opening 45a of first communicating path 45 is disposed
closely and facing to the wall of suction muffler 40, and the
pressure pulsation becomes maximum at opening 45a, so that the wall
nearest and facing to opening 45a is excited. As a result, the
pulsation sound of the refrigerant radiates outside suction muffler
40 to increase the noises.
[0015] FIG. 9 shows a sectional view illustrating suction muffler
50 of another conventional compressor. This another conventional
compressor is described hereinafter with reference to FIG. 9. The
structure of this compressor is the same as the foregoing
conventional one except suction muffler 50, thus detailed
descriptions of the compressor are omitted.
[0016] In FIG. 9, suction muffler 50 includes resonant space 58
which surrounds suction space 57. First communicating path 55 has a
first end open to suction space 57 and a second end communicating
with compressing room 22 via suction valve 34. First communicating
path 55 communicates with resonant space 58 via communicating hole
59. Second communicating path 56 has a first end communicating with
container 1 and a second end communicating with suction space
57.
[0017] An operation of the foregoing compressor is described
hereinafter. Refrigerant gas kept at a low temperature and returned
from a refrigerating system (not shown) is sucked from second
communicating path 56 into suction space 57 of suction muffler 50.
The gas is then sucked from first communicating path 55 into
compressing room 22. At this time, since suction space 57 is
surrounded by resonant space 58, suction space 57 is thermally
insulated by the refrigerant gas in resonant space 58 and the wall
of resonant space 58. This structure prevents the refrigerant gas
in suction space 57 from being heated directly by refrigerant gas
kept at a high temperature and remaining in hermetic container 1.
As a result, the refrigerant gas of a high density can be sucked
into compressing room 22, thereby increasing suction efficiency.
Since resonant space 58 communicates with the suction space via
communicating hole 59, resonant space 58 works also as a resonant
space, thereby reducing noises.
[0018] However, in this conventional structure, suction space 57,
which is an element of suction muffler 50, is surrounded by
resonant space 58. Thus this structure prevents the refrigerant gas
in suction space 57 from being heated directly by refrigerant gas
kept at a high temperature in hermetic container 1, thereby
increasing the suction efficiency. However, similar to the previous
conventional compressor, the refrigerant gas sucked from second
communicating path 56 into suction space 57 forms a large eddy
before it reaches first communicating path 55, so that substantial
pressure loss is produced. As a result, compressing room 22
decreases mass-flow rate of the refrigerant gas to be sucked
therein, so that suction efficiency is lowered.
[0019] Suction space 57 is entirely surrounded by resonant space
58, so that suction muffler 50 as a whole becomes bulky, and needs
a large number of components, or requires a complicated
molding.
DISCLOSURE OF THE INVENTION
[0020] The hermetic compressor of the present invention comprises
the following elements: [0021] a hermetic container including an
electric motor unit and a compressing unit driven by the electric
motor unit, [0022] the compressing unit having a suction valve
disposed at an opening of a compressing room and a suction muffler,
[0023] the suction muffler having the elements below: [0024] a
suction muffler body forming a sound-deadening space; [0025] a
first communicating path for communicating with the suction valve
and with the sound-deadening space; and [0026] a second
communicating path for communicating with the hermetic container
and with the sound-deadening space.
[0027] An opening of the first communicating path in the
sound-deadening space and that of the second communicating path in
the same space are open together in the same direction. A wall of
the suction muffler body has a sound insulating wall at least on a
place facing both of the openings situated in the sound-deadening
space.
[0028] This structure allows suppressing the heating of the gas
sucked into the suction muffler, thereby increasing the efficiency.
The sound-insulating wall exerts its sound absorption capability,
so that reflected wave propagating from the compressing room to the
wall of the muffler body via the first communicating path is
suppressed. As a result, sound transmission can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] FIG. 1 shows a sectional view of a hermetic compressor in
accordance with a first exemplary embodiment of the present
invention.
[0030] FIG. 2 shows a sectional view of a suction muffler in
accordance with the first exemplary embodiment of the present
invention.
[0031] FIG. 3 shows a perspective exploded view of the suction
muffler in accordance with the first exemplary embodiment of the
present invention.
[0032] FIG. 4 shows a sectional view of a suction muffler in
accordance with a second exemplary embodiment of the present
invention.
[0033] FIG. 5 shows flow-rate vectors in the suction muffler in
accordance with the second exemplary embodiment of the present
invention.
[0034] FIG. 6 shows a sectional view of a conventional hermetic
compressor.
[0035] FIG. 7 shows a sectional view of a suction muffler of the
conventional hermetic compressor.
[0036] FIG. 8 shows flow-rate vectors in the suction muffler of the
conventional hermetic compressor.
[0037] FIG. 9 shows a sectional view of a suction muffler of the
conventional hermetic compressor.
PREFERRED EMBODIMENTS OF THE INVENTION
[0038] Exemplary embodiments of the present invention are
demonstrated hereinafter with reference with the accompanying
drawings.
Exemplary Embodiment 1
[0039] FIG. 1 shows a sectional view of a hermetic compressor
(hereinafter referred to simply as a compressor) in accordance with
the first exemplary embodiment of the present invention.
[0040] FIG. 2 shows a sectional view of a suction muffler of the
compressor in accordance with the first embodiment. FIG. 3 shows a
perspective exploded view of the suction muffler of the compressor
in accordance with the first embodiment.
[0041] In FIG. 1, hermetic container 101 accommodates the following
elements: [0042] electric motor unit 105 formed of stator 103 with
windings 102 and rotor 104; [0043] compressing unit 106 to be
driven by electric motor unit 105; and [0044] oil 108 pooled
therein.
[0045] Next, a rough structure of compressing unit 106 is
described. Crankshaft 110 includes main-shaft 111 to which rotor
104 is press-fitted, and off-center section 112 eccentric from main
shaft 111. Oil pump 113 is disposed inside main shaft 111 and open
in oil 108. Cylinder block 120 disposed above electric motor unit
105 has cylindrical compressing room 122 and bearing 123 which
rotatably supports main shaft 111. Piston 130 is inserted into
compressing room 122 such that it can reciprocate in compressing
room 122, and coupled to off-center section 112 via coupler
131.
[0046] Valve plate 135 seals an opening of compressing room 122,
and valve plate 135 includes suction hole 138, which can
communicate with compressing room 122 when suction valve 134 opens.
Cylinder head 136 is fixed opposite to compressing room 122 via
valve plate 135. Suction pipe 137 is fixed to hermetic container
101 and coupled to a lower pressure side (not shown) of a
refrigerating cycle for guiding refrigerant gas (not shown) into
hermetic container 101. Suction muffler 140 is made of synthetic
resin, such as polybutylene-terephtalate to which glass fiber is
mainly added, and rigidly sandwiched by valve plate 135 and
cylinder head 136.
[0047] In FIGS. 2 and 3, suction muffler 140 includes suction
muffler body 141, suction muffler lid 142, first communicating path
145, and second communicating path 146. Suction muffler 140 forms
sound-deadening space 143 therein. In sound-deadening space 143,
openings 145a and 146a are open in the same direction.
Sound-insulating wall 151 is disposed on the wall of muffler body
141 at the place at least facing both of openings 145a and 146a.
Sound insulating wall 151 and an outer wall of muffler body 141
form dual walls, which define blocked space 150. Sound-insulating
wall 151 thus works as a part of suction muffler body 141 and as a
wall which partitions off blocked space 150 from sound-deadening
space 143.
[0048] Sound-insulating wall 151 is disposed vertically with
respect to a parting surface (opening face of the muffler body) of
molding the synthetic resin. After first communicating path 145 is
assembled into muffler body 141, weld protrusion 145b is positioned
to hole 142b punched on lid 142. Then muffler body 141 is bonded to
lid 142 by a ultrasonic welding method, thereby completing suction
muffler 140.
[0049] An operation of the foregoing hermetic compressor is
demonstrated hereinafter. In conventional suction muffler 40, a
temperature of refrigerant gas increases by approx. 10K during the
travel from opening 46b to opening 45b, then the gas is sucked
eventually into compressing room 22. The temperature of the
refrigerant gas also increases by approx. 4K during the travel from
opening 46a, where the gas is discharged into sound-deadening space
43, to opening 45a.
[0050] However, in this embodiment, blocked space 150 is formed in
a part of the wall of suction muffler 140, namely, heat-insulating
effect is increased at the part of the wall, so that
heat-insulation is effectively obtainable with a smaller space than
the conventional muffler which is entirely covered with dual walls.
As a result, the refrigerant gas can be advantageously kept at a
low temperature and at a high density, thereby increasing the mass
flow rate of the gas sucked.
[0051] The foregoing reduction of heating the refrigerant gas can
suppress the temperature hike not more than 2K between openings
146a and 145a, so that refrigerating capacity increases by 1.5%
comparing with that of the conventional muffler, and the efficiency
(COP=coefficient of performance) increases by not less than
1.0%.
[0052] On the other hand, the refrigerant gas in suction muffler
140 becomes an intermittent current in response to the
reciprocating motion of piston 130. At this time, pressure
pulsation propagates inversely to the flow of the refrigerant gas
from compressing room 22 to opening 1.sup.45a of first
communicating path 145, and generates reflected wave toward the
wall nearest and facing to opening 145a. Sound-absorption effect of
blocked space 150 formed of sound-insulating wall 151 suppresses
the transmission of the reflected wave to the outside of suction
muffler 140. In addition to this suppression, sound-insulating wall
151 reinforces the strength of the outer frame of suction muffler
140, thereby preventing suction muffler 140 from being excited by
the reflected wave. This prevention is particularly effective to
reduction of sound transmission at high-frequency component in the
audible band.
[0053] Vertical placement of sound-insulating wall 151 with respect
to the parting surface (opening surface of the muffler body) in
molding of suction muffler 140 makes a drafting direction of the
mold of muffler body 141 agree with that of sound-insulating wall
151. This structure thus prevents the molds from being complicated
in drafting directions and increasing the number of components due
to separating some components. As a result, the structure invites
no additional cost to the molds and allows manufacturing the
suction muffler with ease.
[0054] In this embodiment, blocked space 150 formed by
sound-insulating wall 151 is completely isolated from
sound-deadening space 143; however, communicating holes are punched
on sound-insulating wall 151 so that blocked space 150 can work as
a resonant room, thereby further increasing the sound-insulating
effect.
[0055] In this embodiment, sound-insulating wall 151 is disposed in
suction muffler 140 for defining blocked space 150; however, a
structure separate from the muffler is disposed outside the muffler
so that a blocked space can be formed, thereby obtaining a similar
advantage to this embodiment.
[0056] Second communicating path 146 is unitarily molded with
muffler body 141; however, it can be unitarily molded with lid 142
instead, so that influence of the heat received from electric motor
unit 105 disposed behind muffler body 141 can be reduced.
Exemplary Embodiment 2
[0057] FIG. 4 shows a sectional view of a suction muffler in
accordance with the second exemplary embodiment of the present
invention. FIG. 5 shows flow-rate vectors which show behavior of
the refrigerant gas in the suction muffler in accordance with the
second embodiment. The construction of a hermetic compressor
(hereinafter referred to simply as a compressor) in accordance with
the second embodiment is the same as shown in FIG. 1 except the
suction muffler, so that the description of this embodiment focuses
on the suction muffler.
[0058] In FIG. 4, suction muffler 140 includes suction muffler body
141, a suction muffler lid (not shown), first communicating path
145, and second communicating path 146, and forms sound-deadening
space 143 therein. In this embodiment, a guiding wall 152 is used
as the sound-insulating wall. The guiding wall 152, shaped like
letter U, guides the gas sucked from second communicating path 146,
namely the refrigerant gas, from opening 146a to opening 145a.
[0059] In FIG. 5, flow-rate vectors 160 show behavior, which is
obtained through computer simulation, of the refrigerant gas in
suction muffler 140, and the lengths of respective vectors indicate
a magnitude of flow rate as well as the directions of the vectors
indicate the flow direction of the refrigerant gas. The arrow mark
indicates upper stream 161 formed by the refrigerant gas discharged
from opening 146a of second communicating path 146.
[0060] An operation of the foregoing hermetic compressor is
demonstrated hereinafter. In this embodiment, guiding wall 152
(sound-isolating wall) is disposed for guiding the refrigerant gas
discharged at opening 146a to opening 145a of first communicating
path 145. This structure allows almost all the refrigerant gas
discharged at opening 146a to form upper stream 161, which is then
sucked into first communicating path 145. At this time, the wall of
suction muffler 140 is heated by refrigerant gas kept at a high
temperature in hermetic container 101, and the heated wall heats
the refrigerant gas remaining in sound-deadening space 143. This
heated gas has a temperature higher than that of refrigerant gas
just flowing from second communicating path 146 into
sound-deadening space 143.
[0061] Therefore, sucking as fast as possible almost all the
refrigerant gas discharged at opening 146a into first communicating
path 145 will isolate the gas from the refrigerant gas heated to a
high temperature and remaining in sound-deadening space 143. This
structure allows the refrigerant gas kept at a low temperature and
indicated by upper stream 161 to receive a less amount of heat, so
that the refrigerant gas can be kept at a low density, and the mass
flow rate of the refrigerant to be sucked can be increased.
[0062] Guiding wall 152 shapes like letter U instead of using a
pipe path, so that pressure loss becomes advantageously smaller.
Guiding wall 152 rectifies the refrigerant gas sucked from opening
146a so that the gas can flow smooth, and guides the gas directly
to opening 145a. As a result, the pressure loss can be reduced,
thereby increasing COP. Guiding wall 152 also guides the gas sucked
into compressing room 122 without involving the refrigerant gas
circulating in sound-deadening space 143 but using fluid inertia
force of the gas sucked, so that the mass flow rate of the gas
sucked is increased.
[0063] The mechanism discussed above reduces the heat reception
loss of the refrigerant gas and increases the flow amount of the
gas sucked, so that suction efficiency can increase, refrigerating
capacity improves by 2.5% comparing with the conventional ones, and
COP improves by not less than 2.0%.
[0064] There remains still a problem of reflected wave radiated
from opening 145a to the nearest and confronting wall of suction
muffler 140; however, guiding wall 152 covers opening 145a, thereby
suppressing transmission of the reflected wave through the wall of
suction muffler 140. Guiding wall 152 also prevents the reflected
wave from exciting the wall of suction muffler 140. This prevention
is particularly effective to reduce sound-transmission of high
frequency component in the audible band.
[0065] Further in this embodiment, a clearance of approx. 5 mm is
prepared between opening 145a and guiding wall 152 for maintaining
attenuation effect on the reflected wave generated from opening
145a. However, coupling of opening 145a to the outer circumference
of guiding wall 152 can further reducing the flow resistance of the
refrigerant gas, and the suction efficiency can be improved.
[0066] In this embodiment, descriptions of the specification
identical to that of the first embodiment are omitted; however,
this second embodiment can obtain the advantage of placement
direction of the guiding wall with respect to the parting surface
(an opening face of the suction muffler body) in molding the
synthetic resin.
INDUSTRIAL APPLICABILITY
[0067] A compressing unit of a hermetic compressor of the present
invention includes a suction valve disposed at an opening of a
compressing room and a sucking muffler. The muffler includes a
suction muffler body which forms a sound-deadening space, a first
communicating path which communicates with the suction valve and
with the sound-deadening space, and a second communicating path
which communicates with a hermetic container and with the
sound-deadening space. An opening, situated in the sound-deadening
space, of the first communicating path, and an opening, situated in
the sound-deadening space, of the second communicating path are
both open in the same direction. In addition, a sound-insulating
wall is disposed on the wall of the muffler body at a place at
least confronting both of the openings. Employment of this
compressor in refrigerators, air-conditioners, and refrigerating
plants will reduce noises and improve efficiency of those
apparatuses.
* * * * *