TECHNICAL FIELD
[0001] The present invention relates to a rotary compressor primarily employed in a refrigeration
apparatus.
BACKGROUND ART
[0002] Conventionally, as a rotary compressor, there has been known a compressor described,
for example, in Japanese Utility Model Application Laid-Open Publication No.63-54882.
The conventional compressor is configured, as shown in Fig. 9, so that a roller C
fitted on an eccentric portion S of a drive shaft is installed in a cylinder chamber
A1 of a cylinder A with a front head (not shown) being arranged on one axial end face
of the cylinder A and a rear head (not shown) being arranged on the other end face
thereof, a suction port D and a discharge port E opened to the cylinder chamber A1
are formed at a predetermined interval in the circumferential direction, a blade holding
groove F extending in the radial direction is formed between the suction port D and
discharge port E, a blade G is provided on the blade holding groove F so as to be
movable back and forth and by contacting a tip end of the blade G with the outer circumferential
face of the roller C at all times, the inside of the cylinder chamber A1 is divided
into a suction chamber X communicating to the suction port D and a high pressure chamber
Y communicating to the discharge port E. In addition, the suction port D is positioned
near the blade G on the cylinder A and is formed radially toward the center of the
cylinder chamber A1, in other words, in a direction normal to a tangent at an intersection
point of a center line of the suction port D with an inner circumferential face of
the cylinder chamber A1. It is to be noted here that the roller C is constituted by
two inner and outer roller members.
[0003] In the above-mentioned configuration, however, because the suction port D is formed,
near the blade G, radially toward the central portion of the cylinder chamber A1,
when gaseous fluid flows into the suction chamber X of the cylinder chamber A1 from
the suction port D, after perpendicularly colliding with the outer periphery of the
roller C from the suction port D, the gaseous fluid is introduced toward the counter-blade
side of the suction chamber X approximately in the direction normal to the blade as
indicated by an arrow m in Fig. 9, while being urged to be bounded approximately normal
to the outer periphery of the roller C. As a result, there has been such a problem
that the suction pressure loss in the suction chamber is increased because of the
large flow resistance of the suction gas introduced from the suction port D to the
suction chamber X.
DISCLOSURE OF THE INVENTION
[0005] The object of the present invention is to provide a rotary compressor which is able
to reduce flow resistance in introducing gaseous fluid from a suction port to a low
pressure chamber of a cylinder chamber to reduce suction pressure loss in the low
pressure chamber.
[0006] In order to achieve the above-described object, according to the present invention,
there is provided a rotary compressor which comprises: a cylinder having a cylinder
chamber to which a suction port and a discharge port are opened; a roller fitted on
an eccentric portion of a drive shaft and arranged within the cylinder chamber; and
a blade partitioning the inside of the cylinder chamber into a low pressure chamber
communicating to the suction port and a high pressure chamber communicating to the
discharge port; and wherein the suction port is formed so that a center line of the
suction port at an opening side to the cylinder chamber is inclined toward the blade
with respect to a normal line perpendicular to a tangent of an inner circumferential
surface of the cylinder chamber at an imaginary point at which the center line and
the inner circumferential surface cross each other.
[0007] In the configuration described above, because the suction port is formed so that
the center line of the suction port at least at the opening side to the cylinder chamber
is inclined toward the blade with respect to the normal line perpendicular to the
tangent of the inner circumferential surface of the cylinder chamber at the imaginary
point at which the center line and the inner circumferential surface cross each other,
when gaseous fluid is sucked into the low pressure chamber of the cylinder chamber
from the suction port, the suction gas fluid collides with an outer circumferential
surface of the roller not perpendicularly but at an acute angle relative to a tangent
at the outer circumferential surface. Accordingly, the suction gas after collision
is reflected toward a rotation direction of the drive shaft and introduced smoothly
to the low pressure chamber, and thus, the flow resistance of the suction gas fluid
can be reduced and the pressure loss of the suction gas fluid in the low pressure
chamber can be reduced.
[0008] In another embodiment of the present invention, a center line of the suction port
at a suction pipe connection side is directed to a center of the cylinder chamber.
[0009] Accordingly, when press-fixing the suction pipe or an inlet tube for connecting the
suction pipe into the suction port, the suction pipe and so on can be connected toward
the center of the cylinder and as a result, trouble arising when the suction pipe
or inlet tube is pressed in the same direction as that of the center line of the suction
port at the opening side, that is, trouble of deformations of parts and deviations
in assembly clearance which is likely to take place due to rotating moment applied
to the cylinder when press-inserting it in the direction of the center line at the
opening side, can be eliminated. Furthermore, generally in a rotary compressor, when
a blade is positioned closely to a suction port and a cylinder is combined with the
closing members of front and rear heads by tightening bolts, a sufficient space for
bolt tightening can not obtained between the blade and the suction port, which results
in the decrease in face pressure between the end faces of the cylinder and the closing
members arranged in the axial direction of the cylinder, and consequent leakage between
respective end faces. In the compressor of the embodiment, however, the leakage can
be also eliminated. Furthermore, in the case of supporting the suction pipe with a
coupling tube, if the center line of an entire suction port is inclined so as to make
an acute angle relative to a tangent of an inner circumferential surface of a cylinder
chamber, that is to say, is inclined toward a blade with respect to a normal line
perpendicular to the tangent, the coupling tube must be also fixed to the cylinder
in the direction of this center line and therefore, the coupling tube becomes peculiar
in shape, which prevents sharing parts in common and makes welding difficult. In this
embodiment, the above defect can be also eliminated.
[0010] Accordingly, deformations in parts and deviations in assembly clearance can be prevented
while reducing the pressure loss in the low pressure chamber through reduction of
flow resistance of suction gas, and by securing a sufficient space between the arrangement
position of the blade and the opening side of the suction port, tightening of a bolt
can be made possible, and thus, the leakage from the end faces of the closing members
can be prevented. Furthermore, because the coupling tube to be installed in connecting
the suction pipe can be connected in the direction toward the center of the cylinder,
the commonness of the coupling tube conventionally employed can be achieved and the
welding operation can be also simplified.
[0011] In another embodiment of the present invention, on a closing member provided on one
axial end of the cylinder so as to close one axial end of the cylinder chamber, a
suction passage communicating to a suction pipe is formed so that an end of the suction
passage is inclined toward the cylinder and connected to the suction port.
[0012] With this configuration, even when the cylinder and roller are formed flat by shortening
the axial lengths thereof, suction gas can be introduced from the closing member with
low flow resistance. Namely, in the case of forming a compressor flat by decreasing
the widths of a blade and the roller and compacting the compressor by shortening the
axial lengths thereof or shortening the axial length of one cylinder in using plural
cylinders, the inner diameter of the suction pipe to be connected to the cylinder
becomes smaller and a sufficient size of the suction port can not be obtained according
as the axial length of the compressor is reduced. However, by providing a suction
passage on the closing member such as the rear head, a necessary size of the suction
port can be secured. Also, by inclining the end side of the suction passage toward
the cylinder chamber and connecting the suction passage to the suction port inclined
toward the blade with respect to a normal line perpendicular to the tangent on the
inner circumferential surface of the cylinder chamber, suction gas of a necessary
volume matching the volume of the cylinder chamber can be introduced with low flow
resistance from the suction pipe to the low pressure chamber of the cylinder chamber
via the suction passage and suction port, and thus, the pressure loss in the low pressure
chamber can be reduced.
[0013] In still another embodiment of the present invention, the center line of a suction
passage of a closing member on the inlet side communicating to a suction pipe is directed
toward the center of a cylinder chamber and the center line of the suction passage
at the connection side to a suction port is formed to be inclined in the same direction
as that of the center line of the suction port on the opening side thereof to a cylinder
chamber.
[0014] In this case, the suction pipe can be connected toward the center of the cylinder.
Accordingly, gaseous fluid of a necessary volume corresponding to the volume of the
cylinder chamber can be introduced with low flow resistance into the low pressure
chamber of the cylinder chamber from the suction pipe via the suction passage and
suction port, while reducing pressure loss in the low pressure chamber. Further, deformations
of parts and deviations in assembly clearance can be prevented, and by securing the
necessary space for bolt tightening between the arrangement position of the blade
and the inlet side of the suction port, leakage can be also prevented.
[0015] In still another embodiment, a blade is protrudedly connected to the outer circumferential
surface of a roller, a swing bush having a receiving groove for receiving an end portion
of the blade movably back and forth is swingably held in the cylinder, and a concave
guide groove for guiding the suction gas introduced from the suction port to the low
pressure chamber is provided at the position of the outer circumferential surface
of a roller confronting the suction port formed on the cylinder.
[0016] In this case, the space between the outlet of the suction port and the outer circumferential
surface of the roller can be enlarged, and by this space, the suction resistance of
the suction gas sucked into the cylinder chamber from the suction port can be reduced.
Furthermore, by the guide groove, the suction gaseous fluid can be guided more smoothly
to the side of the low pressure chamber. As a result, flow resistance can be further
reduced and thus, the pressure loss of suction gaseous fluid in the low pressure chamber
can be further reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017]
Fig. 1 is a transverse cross-sectional view showing the essential portion of a rotary
compressor according to a first embodiment of the present invention;
Fig. 2 is an enlarged sectional view taken along line 2-2 in Fig.1;
Fig. 3 is a transverse cross-sectional view showing a second embodiment of the present
invention;
Fig. 4 is a transverse cross-sectional view showing a third embodiment of the present
invention;
Fig. 5 is an enlarged sectional view taken along line 5-5 in Fig. 4;
Fig. 6 is a transverse cross-sectional view showing a fourth embodiment of the present
invention;
Fig. 7 is a partly broken plan view showing a fifth embodiment of the present invention;
Fig. 8 is a longitudinal sectional view showing the overall configuration of a rotary
compressor; and
Fig. 9 is a cross-sectional view showing a conventional rotary compressor.
BEST MODE FOR CARRYING OUT THE INVENTION
[0018] The first embodiment of the present invention is described below with reference to
the accompanying drawings. A rotary compressor shown in Fig. 8 is provided with a
motor 2 arranged on the inner upper portion of a hermetic casing 1 and a compressing
element 4 which is rotatingly driven by a drive shaft 3 extending from the motor 2
is arranged on the lower side of the motor 2. The compressing element 4 is provided
with a cylinder 5 having a cylinder chamber 51 therein, closing members 6, 6 composed
of a front head and a rear head closing both axial ends of the cylinder 5, and a roller
7 fitted on an eccentric portion of the drive shaft 3 and installed within the cylinder
chamber 51.
[0019] In addition, as is clear from Figs. 1 and 2, the cylinder 5 is provided with a suction
port 52 one end of which is connected with a suction pipe 8 inserted from the outside
of the hermetic casing 1 via an inlet tube 81 and the other end of which is opened
to the cylinder chamber 51, a discharge port 53 opened in a discharge space within
the casing 1 and a blade 9 arranged between the suction port 52 and discharge port
53 so as to partition the inner space of the cylinder chamber 51 into a low pressure
chamber X communicating to the suction port 52 and a high pressure chamber Y communicating
to the discharge port 53.
[0020] Furthermore, the rotary compressor of the first embodiment constitutes a swing type
compressor with the blade 9 being arranged to be swingable. In other words, the compressor
is constituted as follows. On a certain portion of the outer circumference of the
roller 7, the blade 9 is embedded at its base end portion so as to radially protrude
outward, and on the cylinder chamber side, in the radial direction of the cylinder
5 and between the suction port 52 and discharge port 53, a circular pillar-shaped
swing bush 10 having a receiving groove 10a for movably receiving an end portion of
the blade 9 is held so as to be rotatable in the circumferential direction. By inserting
the protruded end of the blade 9 into the receiving groove 10a of the swing bush 10
so as to be movable back and forth and swingable, the blade 9 is back and forth moved
in the receiving groove 10a of the bush 10 along with the rotation of the drive shaft
3 and while swinging the blade 9 with respect to the cylinder 5 via the bush 10, the
roller 7 is revolved within the cylinder chamber 51 without rotating, thereby to partition
the internal space of the cylinder chamber 51 into the low pressure chamber X communicating
to the suction port 52 and the high pressure chamber Y communicating to the discharge
port 53.
[0021] In the above-mentioned swing type compressor, because the blade 9 is integrally coupled
with the roller 7, the leakage of high pressure fluid in the high pressure chamber
Y to the low pressure chamber X can be more effectively prevented, because there is
not the leakage through the contact face of a roller with a blade as caused in a rotary
compressor contacting a tip end of a blade with an outer circumference at all times,
and thus, the compression efficiency can be improved. Furthermore, because the blade
9 does not slide along the outer circumference of the roller 7, the friction loss
between the roller 7 and blade 9 can be eliminated and thus power loss can be also
reduced.
[0022] In the above-described configuration of the rotary compressor shown in Figs. 1 and
2, the suction port 52 is formed so that the center line a of the suction port 52
is inclined toward the blade 9, at least on the opening side to the cylinder chamber
51, so as to make an acute angle relative to the tangent b at the intersection point
of the center line a with the inner circumference of the cylinder chamber 51. Namely,
assuming that the center line of the suction port is a, the tangent at the intersection
of the center line a with the inner circumference of the cylinder chamber 51 is b
and a normal line crossing the tangent b at a right angle is c, the suction port 52
is formed on the cylinder 5 so that the center line a of the suction port 52 is inclined
toward the blade 9 side with respect to the line c so as to approach the tangent b.
[0023] As described above, by forming the suction port 52 on the cylinder 5 so that the
center line a of the suction port 52 is inclined toward the blade 9 with respect to
a normal line C perpendicular to the tangent b at the position on the inner circumference
of the cylinder chamber 51 where the suction port 52 is formed, when gaseous fluid
is taken into the low pressure chamber X of the cylinder chamber 51 through the suction
port 52, the suction gaseous fluid does not collide with the outer circumference of
the roller 7 perpendicularly but collide at an acute angle relative to the tangent
at the outer circumference. Therefore the suction gaseous fluid after collision is
reflected in the rotation direction of the drive shaft 3. As a result, suction gaseous
fluid is introduced smoothly into the low pressure chamber X from the suction port
52 with low flow resistance, and thus, the pressure loss in the low pressure chamber
X can be reduced.
[0024] Subsequently, the second embodiment of the present invention is described below.
In a rotary compressor shown in Fig. 3, the shape of a suction port 52 formed in a
cylinder 5 is modified so that a center line d on a suction pipe connection side of
the suction port 52 is directed to the center of a cylinder chamber 51 and the suction
port 52 is bent in the same plane as a cross-section in Fig. 3 so as to incline the
center line a on the opening side of the suction port 52 to the cylinder chamber 51
toward a blade 9 with respect to a normal line c perpendicular to a tangent b at the
intersection point of the center line a with the inner circumferential surface of
the cylinder chamber 51, whereby the later-described trouble taking place in the first
embodiment can be eliminated.
[0025] Specifically, as in the first embodiment, in connecting the suction tube 8 to the
suction port 52 via the inlet tube 81, when the inlet tube 81 is connected by pressfixing
in the direction of the center line a, although there is an effect of reducing pressure
loss through reduction of flow resistance in the cylinder chamber, the action rotating
the cylinder 5 is caused by the pressinsertion in the direction of the center line
a, and troubles such as deformations of components and deviations in assembly clearance
are likely to take place due to rotation moment arising as a result.
[0026] Furthermore, according to the first embodiment, because the arranged positions of
the blade 9 and suction port 52 are too close to each other, a sufficient space for
tightening a bolt can not be obtained between the blade 9 and suction port 52, which
results in leakage through clearances between respective end faces due to face pressure
drop between the end faces of the cylinder 5 and those of the closing members 6 arranged
in the axial direction of the cylinder 5. In addition, when the inlet tube 81 is supported
with a connection tube 82, the connection tube 82 is also to be fixed to the casing
1 in the direction of the center line a and the connection tube 82 takes a special
shape. As a result, it is impossible to use parts employed conventionally, resulting
in the failure to obtain the commonness of parts. In addition, there is a trouble
of difficulty of welding operation.
[0027] As the second embodiment of Fig. 3 shows, by configuring so that the center line
d on the suction pipe connection side of the suction port 52 is directed to the center
of the cylinder and the center line a of the opening side to the cylinder chamber
of the suction port is inclined toward the blade 9 so as to make an acute angle relative
to the tangent b at the intersection point with the inner circumference of the cylinder
chamber 51, the inlet tube 81 can be press-inserted toward the center of the cylinder
5 when connecting the suction pipe 8 with the suction port 52 via the inlet tube 81
and thus, the troubles taking place when the inlet tube 81 is pressinserted in the
same direction as the center line a can be eliminated. As a result, deformations of
parts and deviations in the assembling clearance can be prevented while reducing the
pressure loss in the low pressure chamber X through reduction of flow resistance of
suction gaseous fluid, a sufficient space can be secured between the arranged position
of the blade 9 and the inlet side of the suction port 52, which makes it possible
to arrange a fixing bolt for coupling the closing members 6 and the cylinder 5 between
the blade 9 and suction port 52 and the leakage through between respective end faces
of the cylinder 5 and closing end members 6 can be also prevented. Furthermore, because
the coupling tube 82 employed when press-inserting the inlet tube 81 also can be connected
in the direction toward the center of the cylinder 5, the commonness of coupling tubes
conventionally used in general can be achieved and welding operation also can be conducted
simply.
[0028] Next, the third embodiment is described below with reference to Figs. 4 and 5. As
shown in Fig. 3, in forming the rotary compressor in a flat shape by shortening the
axial length of the roller 7 and blade 9 in such a case of shortening the axial length
of the compressor or constituting the compressor with plural cylinders, when the suction
pipe 8 is connected to the cylinder 5, the inner diameter thereof is affected by the
thickness of the cylinder 5 and as the thickness becomes thinner, the suction tube
size is restricted, leading to the pressure loss. In the rotary compressor shown in
Figs. 4 and 5, one of closing members 6, for example, a lower closing member 6, that
is a rear head is increased in thickness and on this rear head 6, a suction passage
61 is formed so that a center line a of the suction passage 61 is inclined toward
a blade 9 so as to make an acute angle to the tangent b at the intersection point
of the center line a with the inner circumference of the cylinder chamber 51 as shown
in Fig. 4 and the end side of the suction passage 61 is inclined upward toward the
cylinder chamber 51 as shown in Fig. 5 and the suction pipe 8 is connected to the
outer side of the suction passage 61 via the inlet tube 81. On the other hand, the
suction port 52 provided on the cylinder 5 is formed as shown in Fig. 4 so that the
center line a of the suction pipe 8 is inclined toward the blade 9 so as to make an
acute angle relative to the tangent b at the intersection of the center line a with
the inner circumference of the cylinder chamber, similarly to the suction passage
61 and inclined downward so as to be connected with the end side of the suction passage
61. Thereby, the suction pressure loss due to the restriction of the suction port
size can be avoided.
[0029] Namely, by configuring as described above, the inner diameter of the suction passage
61 can be sized sufficiently large irrespective of the thickness of the cylinder 5,
and because the suction passage 61 is connected with the suction port 52 in a slanted
state, suction gaseous fluid can be smoothly introduced into the low pressure chamber
X of the cylinder chamber 51 from the suction passage 61 via the suction port 52 with
a little flow resistance, and thus, the shortage in the suction quantity of gaseous
fluid in the cylinder chamber 51 can be avoided while reducing the pressure loss of
the gaseous fluid in the low pressure chamber X. Namely, even in the case of down-sizing
the cylinder 5 and roller 7 in the axial direction, by configuring as described above,
gaseous fluid can be introduced from the suction passage 61 to the low pressure chamber
X of the cylinder chamber 51 via the suction port 52 with low flow resistance, thus
to reduce the pressure loss in the low pressure chamber X, and the shortage in the
suction gas quantity introduced in the cylinder chamber 51 can be avoided.
[0030] It is to be noted here that in the third embodiment, the blade 9 is formed integrally
with the roller 7 so as to protrude from a part of the outer circumference of the
roller 7.
[0031] In addition, when configuring so as to connect the suction pipe 8 to the closing
member 6 in the case of shortening the axial dimension of the cylinder 5 and roller
7, it is preferable to form so that the center line on the inlet side communicating
with the suction pipe 8 in the suction passage 61 formed in the closing member 6 is
directed to the center of the cylinder chamber 51 and the center line on the connection
side to the suction port 52 of the suction passage 61 is inclined, as shown the fourth
embodiment in Fig. 6, in the same direction as that of the center line on the opening
side to the cylinder chamber 51 of the suction port 52. By doing so, the suction pipe
8 can be connected toward the center of the cylinder chamber 51 via the inlet tube
81 as with the above-described second embodiment. As a result, the necessary quantity
of gaseous fluid matching the volume of the cylinder chamber 51 can be introduced
with reduced flow resistance from the suction pipe 8 to the low pressure chamber X
on the cylinder chamber 51 via the suction passage 61 and suction port 52, and deformations
of parts and deviations in the assembly clearance can be prevented while achieving
the reduction of the pressure loss in the low pressure chamber X. In addition, because
the space for tightening a bolt can be secured between the arranged position of the
blade 9 and the inlet side of the suction port 52, leakage can be also prevented.
[0032] In the embodiment described above, while the suction passage 61 is formed in the
rear head as the lower closing member 6, the suction passage 61 may be formed in the
front head as the upper closing member 6. In a rotary compressor wherein two cylinders
on the upper and lower side are employed with a middle plate being inserted between
the cylinders and gaseous fluid is compressed in the cylinder chamber of each cylinder,
a suction passage can be formed also in the middle plate.
[0033] In addition, in each embodiment described above, description has been made of a swing
type rotary compressor. In the case of configuring such a rotary compressor of swing
type, because the roller 7 is merely revolved around the center of the cylinder chamber
without rotating by the swinging motion of the blade 9, the position of the roller
portion confronting the suction port 52 is invariable. Accordingly, it is preferable
to form, as shown in Fig. 7, a concave guide groove 71 of a circular-arc shape for
more smoothly guiding the suction gas introduced from the suction port 52 to the low
pressure chamber X on the roller outer circumference portion confronting the suction
port 52, by utilizing the revolution motion of the roller 7.
[0034] By adopting the configuration, the space between the outlet of the suction port 52
and the circumferential surface of the roller 7 can be enlarged, and by this space,
the suction resistance of suction gas fluid sucked into the cylinder chamber 51 from
the suction port 52 can be reduced. Further, the suction gas fluid sucked into the
cylinder chamber 51 from the suction port 52 is more smoothly guided into the low
pressure chamber X via the guide groove 71 of a circular-arc shape. Accordingly, the
flow resistance of the gas fluid sucked into the cylinder chamber 51 can be reduced
further and thus, the pressure loss of the suction gas fluid in the low pressure chamber
can be further reduced.
[0035] In addition, in the embodiment shown in Fig. 7, because the guide groove 71 for guiding
the gas fluid sucked from the suction port 52 to the outer circumference of the roller
7 is formed in a concave shape, while the rotary compressor is required to be formed
of a swing type, rotary compressors are not necessarily required to be of a swing
type but may be of a revolving type around the center of the cylinder chamber 51.
In addition, in third and fourth embodiments, while the cylinder 5 and the roller
7 are formed to be flat, in the case of connecting the suction tube 8 to the closing
member 6, the cylinder 5 and roller 7 are not necessarily required to be flat.
INDUSTRIAL APPLICABILITY
[0036] The rotary compressor according to the present invention is employed primarily for
the refrigeration apparatus.