TECHNICAL FIELD
[0001] The present invention relates to a scroll-type compressor configuring an air conditioning
device for indoor use, for example.
BACKGROUND ART
[0002] A scroll-type compressor used in a refrigerating cycle of an air conditioning device,
a refrigerating device, and the like is provided with a stationary scroll and a revolving
scroll. The stationary scroll and the revolving scroll are each formed by a spiral-shaped
wrap wall being integrally formed with one surface of an end plate having a round
shape. Such a stationary scroll and revolving scroll are made to face each other with
the wrap walls mutually engaged, and the revolving scroll is revolved with respect
to the stationary scroll by an electric motor or the like. Then, a compression chamber
formed between the two wrap walls is displaced from an outer circumferential side
to an inner circumferential side while decreasing in volume. As such, a refrigerant
gas within the compression chamber is compressed.
[0003] The refrigerant gas compressed in the compression chamber passes through to an ejection
port formed in the end plate of the stationary scroll, flows into a high-pressure
chamber between a discharge cover and a housing, and is further ejected from an ejection
pipe provided in the housing toward a refrigerant circuit.
[0004] The ejection port formed in the stationary scroll has an influence on the performance
or noise of the scroll-type compressor. As such, various ejection ports have been
proposed.
[0005] For example, in Patent Document 1, in order to suppress vibrations and noise due
to ejection of fluid compressed by the revolving motion of the scroll, fitting a collar
having a hollow tube shape to the ejection port is proposed. Providing such a collar
enables the vibration force of pressure pulses within the tube to be reduced, and
an increase in compressor noise to be suppressed.
CITATION LIST
Patent Literature(s)
[0006] Patent Document 1: japanese Unexaminated utility Model Application Publication No.
H4-82391U
SUMMARY OF INVENTION
Technical Problem
[0007] However, the vibrations and noise produced by the scroll-type compressor occur across
a wide range of frequency. Accordingly, reducing noises in the entire frequency range
using a single noise reduction measure is difficult. As such, there is a need to apply
a countermeasure corresponding to a target frequency for noise reduction. For example,
in Patent Document 1, the volume of the ejection port provided with a collar is limited,
which makes it difficult to reduce the noise of a low-frequency range is difficult.
[0008] The present invention has been made in view of this technological problem, and thus
an object thereof is to provide a scroll-type compressor enabling reduction in the
noise of a desired frequency band produced by the scroll-type compressor.
Solution to Problem
[0009] The resonance frequency in the ejection port may be changed by changing the length
and volume (hereinafter termed specifications) of the ejection port. However, given
restrictions on the dimensions of the scroll-type compressor, the specifications of
the ejection port cannot be largely changed. As such, the resonance frequency cannot
be changed either.
[0010] Therefore, in the present invention, the ejection port provided in the stationary
scroll is partitioned into an upstream port section and a downstream port section
and the volume of the downstream port section is increased, thereby the ejection port
functioning as a muffler. In addition, the downstream port section is partitioned
in order to have a plurality of compartments, thereby realizing a different resonance
frequency than is obtained with a non-partitioned downstream port section. As such,
noise reduction of a desired frequency band is made possible. However, there is a
need for the plurality of partitioned compartments to function as a passage for the
refrigerant in order for the refrigerant to pass through the downstream port section
without waste.
[0011] That is, the scroll-type compressor of the present invention is provided with a revolving
scroll rotatably connected to an eccentric shaft portion of a main shaft, a stationary
scroll facing the revolving scroll to form a compression chamber compressing a refrigerant,
and having an ejection port on an end plate, the ejection port ejecting the compressed
refrigerant toward a high-pressure chamber, and a discharge cover covering the ejection
port.
[0012] The scroll-type compressor of the present invention has the ejection port formed
by an upstream port section provided on an upstream side in an inflow direction of
the refrigerant, and a downstream port section provided on a downstream side in the
inflow direction of the refrigerant, the downstream port section having a greater
volume than the upstream port section. Moreover, the downstream port section is provided
with partitioning wall(s) partitioning the interior of the downstream port section
into a plurality of areas, and with a refrigerant passage passing the refrigerant
through the plurality of areas.
[0013] In the scroll-type compressor of the present invention, the partitioning wall is
provided in the downstream port section of the ejection port, and the specifications
of the partitioning wall, such as the length and height, can be set as desired. That
is, tuning of the partitioning wall is made possible. As a result, sound reduction
in a desired frequency band is enabled by tuning the partitioning wall in correspondence
with the target scroll-type compressor.
[0014] Typically, the ejection port including the downstream port section has a round internal
space (cavity) formed therein. Taking this as a given, the partitioning wall preferably
has a horizontal cross-section in an arc shape. This serves to minimize turbulence
in the flow of refrigerant passing through the downstream port section. The arc-shaped
partitioning wall may be provided in one of singularity and plurality along the circumferential
direction of the downstream port section. In a case where the partitioning wall is
provided in plurality, symmetrically positioning the partitioning walls is preferable
in order to minimize the turbulence in the flow of the refrigerant.
[0015] In the present invention, any means may be used to provide the partitioning wall.
However, forming the partitioning wall integrally with the discharge cover is preferable.
The discharge cover is manufactured by casting, similarly to the revolving scroll
and the stationary scroll. However, integrally forming the partitioning wall by casting
reduces the number of manufacturing processes in comparison to fixing a separately
manufactured partitioning wall. The partitioning wall with a rib is preferably formed
integrally with the discharge cover in order to increase the rigidity.
Advantageous Effects of Invention
[0016] According to the present invention, a partitioning wall is provided in a downstream
port section of a scroll-type compressor and tuning is applied to the partitioning
wall. This produces sound reduction in a desired frequency band and suppresses noise.
Brief Description of Drawing(s)
[0017]
FIG. 1 is a vertical cross-sectional view of a scroll-type compressor of an embodiment.
FIG. 2A is a partial enlarged view of a vicinity of an ejection port of a stationary
scroll of FIG. 1, and FIG. 2B is a perspective view schematically illustrating the
vicinity of the ejection port of FIG. 2A.
FIGS. 3A to 3F are horizontal cross-sectional views for explaining various states
of arrangement of a partitioning wall.
FIGS. 4A to 4C are horizontal cross-sectional views for explaining measures of improving
rigidity of the partitioning wall.
FIG. 5 shows a sound reduction effect of the embodiment.
Description of Embodiments
[0018] The invention is described in detail below on the basis of embodiments illustrated
in the accompanying drawings.
[0019] As illustrated in FIG. 1, a scroll-type compressor 1 of the present embodiment includes
a housing 10 housing an electric motor 12 and a scroll-type compressor mechanism 2
driven by the electric motor 12. The scroll-type compressor 1 compresses a refrigerant
such as R410C or R407C and, for example, supplies the refrigerant to a refrigerant
circuit such as that of an air conditioning device or a refrigerator. The configuration
of the scroll-type compressor 1 is described below.
[0020] The housing 10 is provided with a housing body 101 shaped as a bottomed cylinder
open at a top end, and a housing top 102 covering an opening at the top end of the
housing body 101.
[0021] An intake pipe 13 is provided on a side face of the housing body 101, introducing
the refrigerant from an accumulator (not illustrated) into the housing body 101.
[0022] An ejection pipe 14 is provided on the housing top 102, ejecting the refrigerant
compressed by the scroll-type compressor mechanism 2. The interior of the housing
10 is partitioned by a discharge cover 25 into a low-pressure chamber 10A and a high-pressure
chamber 10B.
[0023] The electric motor 12 is provided with a stator 15 and a rotor 16.
[0024] The stator 15 is provided with a coil generating a magnetic field upon being supplied
with electric power from a power supply unit (not illustrated) that is affixed to
the side face of the housing body 101. The rotor 16 is provided with a permanent magnet
and a yoke as main components, and further joined integrally with a main shaft 17
at the center.
[0025] An upper bearing 18 and a lower bearing 19 are provided at both ends of the main
shaft 17 so as to interpose the electric motor 12, rotatably supporting the main shaft
17.
[0026] An accommodating space 190 is formed in the upper bearing 18. An eccentric pin 17A
provided on the top end of the main shaft 17 protrudes and is accommodated by the
accommodating space 190.
[0027] The scroll-type compressor mechanism 2 is provided with a stationary scroll 20 and
a revolving scroll 30 configured to revolve with respect to the stationary scroll
20.
[0028] The stationary scroll 20 is provided with a stationary end plate 21 and a wrap 22
having a spiral shape originating from one face of the stationary end plate 21. The
stationary scroll 20 also includes an ejection port 23 provided on the stationary
end plate 21.
[0029] As illustrated in FIG. 2A, the ejection port 23 includes an upstream port section
23A and a downstream port section 23B that communicates with the upstream port section
23A and has a greater volume than the upstream port section 23A. Both the upstream
port section 23A and the downstream port section 23B have round-shaped openings (cavities).
The upstream port section 23A is disposed on an upstream side in a direction A of
the flow of the refrigerant, and the downstream port section 23B is disposed on a
downstream side thereof. Enlarging an opening surface area of the downstream port
section 23B, positioned on the downstream side in the direction A, enables a reduction
in pressure loss for the refrigerant in that section. Here, FIG. 2B only illustrates
the surrounding vicinity of the downstream port section 23B with the discharge cover
25 removed, relating to the stationary end plate 21. The same applies to FIGS. 3A
to 3F, described later.
[0030] The upstream side of the upstream port section 23A communicates with a compression
chamber PR formed between the stationary scroll 20 and the revolving scroll 30. In
addition, the downstream side of the downstream port section 23B communicates with
an ejection port 27 of the discharge cover 25 covering the top of the stationary scroll
20.
[0031] A partitioning wall 40 is provided in the downstream port section 23B. The partitioning
wall 40 is formed of partitioning walls 40a, 40b having identical shapes and identical
dimensions, each having a horizontal cross-section in an arc shape.
[0032] The partitioning wall 40 partitions the downstream port section 23B into an outside
area OA and an inside area IA, thus changing the natural frequency of the downstream
port section 23B. The partitioning walls 40a, 40b are symmetrically disposed centered
on the center C of the downstream port section 23B. Symmetrically disposing the partitioning
wall 40 enables turbulence in the flow of the refrigerant in the downstream port section
23B to be minimized. A gap G is provided between end portions E, E of the partitioning
walls 40a, 40b in the circumferential direction. This gap G is provided across the
entirety of the partitioning walls 40a, 40b in the height direction, and makes the
outside area OA communicate with the inside area IA in the radial direction. The refrigerant
flowing into the downstream port section 23B passes through the refrigerant passage
connecting the outside area OA, the gap G, and the inside area IA, and flows into
the ejection port 27 of the discharge cover 25.
[0033] The partitioning wall 40 is integrally formed with the discharge cover 25 and is
provided so that a tip of the partitioning wall 40 is in contact with a surface of
the stationary end plate 21.
[0034] The action and effect obtained by providing the partitioning wall 40 are described
later.
[0035] The revolving scroll 30 is likewise provided with a revolving end plate 31 having
a round shape, and a wrap 32 having a spiral shape originating from one face of the
revolving end plate 31.
[0036] A boss 34 is provided on a back face of the revolving end plate 31 of the revolving
scroll 30, and a drive bush 36 is assembled on the boss 34 through a bearing. The
eccentric pin 17A is fit into the drive bush 36. As a result, the revolving scroll
30 is eccentrically joined to a shaft center of the main shaft 17. As such, upon rotation
of the main shaft 17, the revolving scroll 30 rotates (revolves) with an eccentric
distance from the shaft center of the main shaft 17 as a radius of revolution.
[0037] Here, an Oldham's ring (not illustrated) is provided between the revolving scroll
30 and the main shaft 17 in order to restrain the rotation of the revolving scroll
30 so that the revolving scroll 30 does not rotate upon itself while revolving.
[0038] The wraps 22, 32 have a predetermined amount of eccentricity with respect to each
other, engage with each other with a phase offset of 180°, and are in contact with
each other at a plurality of positions according to a rotation angle of the revolving
scroll 30. Then, the compression chamber PR is formed with point symmetry with respect
to a central portion (innermost circumferential portion) of the spirals of the wraps
22, 32. Also, as the revolving scroll 30 revolves, the compression chamber is displaced
gradually toward the inner circumferential side while decreasing in volume. Then,
the refrigerant is maximally compressed at the central portion of the spirals. The
compression chamber PR illustrated in FIG. 1 depicts this portion.
[0039] In the scroll-type compressor mechanism 2, the volume of the compression chamber
PR formed between the two scrolls 20, 30 is also reduced in the height direction of
the wraps in the middle of the spirals. To this end, the height of the wrap in both
of the stationary scroll 20 and the revolving scroll 30 is less on the inner circumferential
side than the outer circumferential side. Also, an end plate on an opposite side of
the stepwise wraps is made to protrude inward to a greater extent at the inner circumferential
side than the outer circumferential side.
[0040] The scroll-type compressor 1 provided with the above-described configuration is subject
to excitation of the electric motor 12 and introduction of the refrigerant into the
housing 10 through the intake pipe 13.
[0041] Upon excitation of the electric motor 12, the main shaft 17 rotates, thereby revolving
the revolving scroll 30 with respect to the stationary scroll 20. Then, the refrigerant
is compressed in the compression chamber PR between the revolving scroll 30 and the
stationary scroll 20, and the refrigerant introduced into the low-pressure chamber
10A within the housing 10 from the intake pipe 13 is taken in between the revolving
scroll 30 and the stationary scroll 20. Afterward, the refrigerant compressed in the
compression chamber PR passes through the ejection port 23 of the stationary end plate
21 and the ejection port 27 of the discharge cover 25 in the stated order and is ejected
into the high-pressure chamber 10B, and is then further ejected to the outside from
the ejection pipe 14. As such, the intake, compression, and ejection of the refrigerant
are continuously performed.
[Action and Effects]
[0042] Next, the actions and effects obtained by providing the partitioning wall 40 in the
downstream port section 23B are described.
[0043] The refrigerant compressed by the stationary scroll 20 and the revolving scroll 30
is ejected from the compression chamber PR to the upstream port section 23A, and passes
through the upstream port section 23A and the downstream port section 23B in the stated
order. The refrigerant having passed through the downstream port section 23B is ejected
from the ejection port 27 into the high-pressure chamber 10B.
[0044] The refrigerant ejected into the high-pressure chamber 10B through this pathway produces
a resonance at a frequency corresponding to each of the ejection ports. The production
of this resonance causes a dramatic increase in amplitude of vibration of the ejection
port, resulting in noise being increased.
[0045] As such, in the present embodiment, the internal space of the downstream port section
23B is partitioned into the outside area OA and the inside area IA by providing the
partitioning wall 40 in the downstream port section 23B. Doing so changes the natural
frequency of the downstream port section 23B relative to a case where the partitioning
wall 40 is not provided. Changing the natural frequency in this manner enables a reduction
in sound of a desired frequency band.
[0046] Here, in the present embodiment, the reduction in sound may be applied to a desired
frequency band by setting a length L of the partitioning wall 40 to 1/2 the wavelength
λ of the sound to be reduced.
[0047] The principles of sound reduction applied to the sound of a desired frequency are
as follows.
[0048] Typically, the following relationship (Expression 1) holds for a sound velocity c,
a frequency f, and a wavelength λ.

where c is a sound velocity in m/s; f is a frequency in Hz; and λ is a wavelength
in m.
[0049] Determining the frequency f of the sound to be reduced enables the wavelength λ to
be calculated from Expression 1. Then, the length L of the partitioning wall 40 is
set to 1/2 of the wavelength λ thus calculated.
[0050] Here, there is a tendency such that the longer the length L of the partitioning wall
40, the lower the frequency of the sound reduced, and conversely, the shorter the
length of the partitioning wall 40, the higher the frequency of the sound reduced.
Moreover, not only the length L but also the height T of the partitioning wall 40
may be subject to the tuning of the partitioning wall 40.
[0051] In order to confirm the effect of the present embodiment, the relationship between
frequency and amount of sound reduction was investigated using both a compressor provided
with the partitioning wall 40 and a compressor not provided with the partitioning
wall 40. The results are given in FIG. 5. The amount of sound reduction is indicated
on the vertical axis. A larger value indicates a greater amount of sound reduction.
[0052] As shown in FIG. 5, providing the partitioning wall 40 for a frequency band of 1.6
kHz, for example, was found to reduce sounds by approximately 25 dB. Similarly, providing
the partitioning wall 40 was found to enable the promotion of sound reduction in the
frequency band of from 4.0 kHz to 5.0 kHz.
[0053] Given the above results, providing the partitioning wall 40 in the downstream port
section 23B was confirmed as being able to reduce sounds corresponding to 1.6 kHz
and 4.1 kHz, which are sources of noise.
[Examples of Partitioning Wall Shape]
[0054] The embodiment has been described above as symmetrically providing the two partitioning
walls 40a, 40b having identical shapes and identical dimensions. However, the present
invention is not limited in this manner. Various modifications to the shape pattern
of the partitioning wall 40 may be added. Several examples are illustrated, with reference
to FIGS. 3A to 3F.
[0055] For example, the partitioning walls 40a, 40b may be connected by a portion at one
of the gaps G, thus forming the partitioning wall 40 in a C shape as illustrated in
FIG. 3A. As such, the length L of the arc of the partitioning wall 40 is increased,
thus enabling a reduction in sound of a lower frequency.
[0056] In addition, as illustrated in FIG. 3B, a center of symmetry C' of the partitioning
wall 40 (40a, 40b) may be provided at a position having eccentricity with respect
to the center C of the downstream port section 23B.
[0057] In addition, as illustrated in FIG. 3C, the partitioning walls 40a, 40b having different
arc lengths may be used. Doing so enables sounds of different frequency bands to be
reduced. In such a situation, as illustrated in FIG. 3C, the respective distances
from the center C to the partitioning walls 40a, 40b may be different from each other.
[0058] In addition, as illustrated in FIG. 3D, the partitioning wall 40 may be provided
as divided into three or more pieces (three in FIG. 3D). Providing the partitioning
wall 40 in plurality enables the sound reduction effect to be increased.
[0059] In addition, as illustrated in FIG. 3E, partitioning walls 40A, 40C, 40B, 40D may
be doubly provided with spacing in the radial direction. In such a case, the downstream
port section 23B is partitioned into a plurality of areas. That is, each of the partitioning
walls 40A to 40D partitions the downstream port section 23B into an inside area and
an outside area in terms of the radial direction.
[0060] The overall length L of the arc of the partitioning wall 40 is increased, which is
effective in a case where an increase in the sound reduction effect is desired. The
partitioning walls 40 are not limited to being provided doubly, and may also be provided
triply or more.
[0061] Furthermore, as illustrated in FIG. 3F, the partitioning wall 40 may have a spiral
shape. The partitioning wall 40 having the spiral shape partitions the downstream
port section 23B into an inside area surrounded by the partitioning wall 40 in the
radial direction and an outside area of the outermost circumference of the partitioning
wall 40.
[0062] The length L of the partitioning wall 40 may be increased with the partitioning wall
40 having the spiral shape. As such, this configuration is effective for reducing
sound of a lower frequency.
[0063] Here, the refrigerant flowing in from the upstream port section 23A passes through
the downstream port section 23B while flowing in a spiral along the partitioning wall
40, and is ejected to the ejection port 27.
[0064] The shapes illustrated in FIGS. 3A to 3F may be combined as appropriate.
[0065] In addition, no limitation is intended to the arc shape (or oval arc shape) of the
horizontal cross-section. For example, the partitioning wall 40 may have any of various
shapes, including a linear shape, a U shape, and the like. Furthermore, in a case
where a plurality, for example, two, of the partitioning walls 40a, 40b are provided,
a non-symmetric arrangement may also be applied. In essence, any shape may be used
for the partitioning wall provided that tuning of the partitioning wall in accordance
with a frequency band of sound to be reduced is possible.
[Rigidity Improvement Example]
[0066] Next, there is a need to provide the partitioning wall 40 with rigidity in order
to withstand the pressure from the refrigerant passing through the ejection port 23.
Here, the term rigidity is used entirely in reference to a joining portion with the
discharge cover 25.
[0067] In the present embodiment, as illustrated in FIG. 4A, the end portions E, E of the
partitioning walls 40a, 40b each may be provided with a rib 41 extending toward the
outside in the radial direction. Providing these ribs 41 improves the rigidity of
the partitioning walls 40a, 40b with respect to the pressure of the refrigerant from
the inside area IA to the outside in the radial direction. The ribs 41 have the same
height as the partitioning wall 40, and equal thickness in the height direction. However,
no such limitation is intended provided that the effect of rigidity improvement is
obtained.
[0068] The ribs 41 serve to form a throttle, in addition to serving the function of rigidity
improvement. That is, providing the ribs 41 causes a port 44 of the refrigerant from
the inside area IA to the outside area OA to be throttled. As such, the effect of
sound reduction is increased.
[0069] In addition to the rib 41, as illustrated in FIG. 4B, a rib 42 may also be provided
at any position between the end portions E, E, for example at a median position. Doing
so provides further improvement to the rigidity of the partitioning wall 40, and also
forms a partitioning wall 50 having a length of 1/2 L between the rib 41 and the rib
42. As such, sound of a high frequency may also be reduced.
[0070] In order to improve the rigidity, as illustrated in FIG. 4C, a partitioning wall
43 having a wave-shaped horizontal cross-section may be applied. The partitioning
wall 43 has portions corresponding to peaks and troughs of the wave shape producing
a similar effect to the rib 41. Further, these portions are present in plurality,
resulting in the partitioning wall 43 having higher rigidity.
[0071] The embodiments have been described above. However, as long as there is no departure
from the spirit and scope of the present invention, configurations described in the
above embodiments can be selected as desired, or can be changed to other configurations
as necessary.
[0072] For example, provided that the downstream port section 23B is partitioned into the
outside area OA and the inside area IA, the partitioning wall 40 is not limited to
being integrally formed with the discharge cover 25. For example, the partitioning
wall 40 may also be integrally formed with the stationary end plate 21, or may be
separately manufactured from the stationary end plate 21 and the discharge cover 25
and fixed to the downstream port section 23B at a predetermined position using an
appropriate approach.
[0073] Furthermore, the tip of the partitioning wall 40 do not have to be in contact with
the stationary end plate 21. The tip of the partitioning wall 40 may be separated
from the stationary end plate 21, provided that the effect of noise reduction is obtained
by the partitioning wall.
Reference Signs List
[0074]
1 Scroll-type compressor
2 Scroll-type compressor mechanism
10 Housing
10A Low-pressure chamber
10B High-pressure chamber
12 Electric motor
13 Intake pipe
14 Ejection pipe
15 Stator
16 Rotor
17A Main shaft
17A Eccentric pin
18 Upper bearing
19 Lower bearing
20 Stationary scroll
21 Stationary end plate
22, 32 Wrap
23 Ejection port
23A Upstream port section
23B Downstream port section
25 Discharge cover
27 Ejection port
30 Revolving scroll
31 Revolving end plate
34 Boss
36 Drive bush
40, 40a to 40d, 43 Partitioning wall
41, 42 Rib
44 Port
101 Housing body
102 Housing top
190 Accommodating space
A Direction
OA Outside area
IA Inside area
C, C' Center
G Gap
PR Compression chamber