U.S. patent application number 10/773694 was filed with the patent office on 2004-09-16 for piston type compressor.
Invention is credited to Inoue, Yoshinori, Kawachi, Shigeki, Kawaguchi, Masahiro, Kawamura, Hisato, Mochizuki, Kenji, Ota, Masaki, Takahata, Junichi, Tarutani, Tomoji.
Application Number | 20040179951 10/773694 |
Document ID | / |
Family ID | 32653014 |
Filed Date | 2004-09-16 |
United States Patent
Application |
20040179951 |
Kind Code |
A1 |
Ota, Masaki ; et
al. |
September 16, 2004 |
Piston type compressor
Abstract
A piston type compressor has introducing passages, each
extending from one of compression chambers, and a cylindrical
rotary valve located between a suction pressure zone and the
introducing passages. An opening of each of the introducing
passages has an advanced area a part of that is inclined relative
to an axial direction and a circumferential direction of the rotary
valve. The rotary valve has a residual gas bypass passage. The
residual gas bypass passage connects a high pressure introducing
passage through the introducing passages, which communicates with
the high pressure compression chamber after the discharge stroke
ends, to a low pressure introducing passage, which communicates
with the low pressure compression chamber. When a high pressure
opening of the residual gas bypass passage starts to be connected
with the opening of one of the introducing passages, an advanced
area of the high pressure opening of the residual gas bypass
passage extends along the advanced area of the opening of the
introducing passage.
Inventors: |
Ota, Masaki; (Kariya-shi,
JP) ; Tarutani, Tomoji; (Kariya-shi, JP) ;
Kawamura, Hisato; (Kariya-shi, JP) ; Inoue,
Yoshinori; (Kariya-shi, JP) ; Kawachi, Shigeki;
(Kariya-shi, JP) ; Takahata, Junichi; (Kariya-shi,
JP) ; Mochizuki, Kenji; (Kariya-shi, JP) ;
Kawaguchi, Masahiro; (Kariya-shi, JP) |
Correspondence
Address: |
MORGAN & FINNEGAN, L.L.P.
345 Park Avenue
New York
NY
10154
US
|
Family ID: |
32653014 |
Appl. No.: |
10/773694 |
Filed: |
February 5, 2004 |
Current U.S.
Class: |
417/269 ;
417/222.2 |
Current CPC
Class: |
F04B 27/1018
20130101 |
Class at
Publication: |
417/269 ;
417/222.2 |
International
Class: |
F04B 001/12 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2003 |
JP |
2003-030890 |
Claims
1. A piston type compressor comprising: a suction pressure zone; a
discharge pressure zone; a rotary shaft; a piston type compression
mechanism, wherein the compression mechanism includes a plurality
of cylinders and pistons, wherein each piston is accommodated in
one of the cylinders, and defines a compression chamber in the
associated cylinder, wherein, as the rotary shaft rotates, each
piston draws gas from the suction pressure zone into the associated
compression chamber, compresses the gas in the compression chamber,
and discharges the gas to the discharge pressure zone; a plurality
of introducing passages, each extending from one of the compression
chambers; and a cylindrical rotary valve located between the
suction pressure zone and the introducing passages, wherein the
rotary valve rotates synchronously with rotation of the rotary
shaft, wherein the rotary valve has a suction communicating passage
and a residual gas bypass passage, wherein, as the rotary shaft
rotates, the suction communicating passage consecutively connects,
through the corresponding introducing passage, the suction pressure
zone with a compression chamber corresponding to a piston in the
suction stroke, and wherein the residual gas bypass passage
connects the introducing passage that extends from one of the
compression chambers in which the discharge stroke has been
finished, or a high pressure introducing passage, with the
introducing passage that extends from one of the compression
chambers the pressure of which is lower than the pressure in the
high pressure introducing passage, wherein each introducing passage
has an opening that faces the outer surface of the rotary valve,
wherein the bypass passage has a high pressure opening, and
wherein, as the rotary valve rotates, the high pressure opening is
consecutively connected with the opening of the high pressure
introducing passage, wherein a peripheral portion of the opening of
each introducing passage has a first advancing area, wherein, when
the high pressure opening starts to be connected with the opening
of the introducing passage, the high pressure opening overlaps the
first advancing area, and wherein the first advancing area has a
first inclined portion that is inclined relative to an axial
direction and a circumferential direction of the rotary valve, and
wherein a peripheral portion of the high pressure opening has a
second advancing area, wherein, when the high pressure opening
starts being connected with the opening of one of the introducing
passages, the second advancing area overlaps the opening of the
introducing passage, and wherein the second advancing area has a
second inclined portion, and wherein, when the high pressure
opening starts being connected with the opening of one of the
introducing passages, the second inclined portion extends along the
first inclined portion.
2. The compressor according to claim 1, wherein, when the high
pressure opening starts being connected with the opening of one of
the introducing passages, the entire second inclined portion
overlaps the first inclined portion.
3. The compressor according to claim 2, wherein the each first
inclined portion has a curved portion, and wherein the second
inclined portion conforms to the shape of the curved portions.
4. The compressor according to claim 1, wherein a peripheral
portion of the opening of each introducing passage has a first
trailing area, wherein, when the high pressure opening finishes
being connected with the opening of the introducing passage, the
high pressure opening passes over the first trailing area, and
wherein the first trailing area has a first inclined portion that
is inclined relative to an axial direction and a circumferential
direction of the rotary valve, and wherein a peripheral portion of
the high pressure opening has a second trailing area, wherein, when
the high pressure opening finishes being connected with the opening
of one of the introducing passages, the second trailing area passes
over the opening of the introducing passage, and wherein the second
trailing area has a second inclined portion, and wherein, when the
high pressure opening finishes being connected with the opening of
one of the introducing passages, the second inclined portion
extends along the first inclined portion.
5. The compressor according to claim 4, wherein, when the high
pressure opening finishes being connected with the opening of one
of the introducing passages, the entire second inclined portion
overlaps the first inclined portion.
6. The compressor according to claim 5, wherein the each first
inclined portion has a curved portion, and wherein the second
inclined portion conforms to the shape of the curved portions.
7. A piston type compressor comprising: a suction pressure zone; a
discharge pressure zone; a rotary shaft; a piston type compression
mechanism, wherein the compression mechanism includes a plurality
of cylinders and pistons, wherein each piston is accommodated in
one of the cylinders, and defines a compression chamber in the
associated cylinder, wherein, as the rotary shaft rotates, each
piston draws gas from the suction pressure zone into the associated
compression chamber, compresses the gas in the compression chamber,
and discharges the gas to the discharge pressure zone; a plurality
of introducing passages, each extending from one of the compression
chambers; and a cylindrical rotary valve located between the
suction pressure zone and the introducing passages, wherein the
rotary valve rotates synchronously with rotation of the rotary
shaft, wherein the rotary valve has a suction communicating passage
and a residual gas bypass passage, wherein, as the rotary shaft
rotates, the suction communicating passage consecutively connects,
through the corresponding introducing passage, the suction pressure
zone with a compression chamber corresponding to a piston in the
suction stroke, and wherein the residual gas bypass passage
connects the introducing passage that extends from one of the
compression chambers in which the discharge stroke has been
finished, or a high pressure introducing passage, with the
introducing passage that extends from one of the compression
chambers the pressure of which is lower than the pressure in the
high pressure introducing passage, wherein each introducing passage
has an opening that faces the outer surface of the rotary valve,
wherein the bypass passage has a high pressure opening, and
wherein, as the rotary valve rotates, the high pressure opening is
consecutively connected with the opening of the high pressure
introducing passage, wherein a peripheral portion of the opening of
each introducing passage has a first trailing area, wherein, when
the high pressure opening finishes being connected with the opening
of the introducing passage, the high pressure opening passes over
the first trailing area, and wherein the first trailing area has a
first inclined portion that is inclined relative to an axial
direction and a circumferential direction of the rotary valve, and
wherein a peripheral portion of the high pressure opening has a
second trailing area, wherein, when the high pressure opening
finishes being connected with the opening of one of the introducing
passages, the second trailing area passes over the opening of the
introducing passage, and wherein the second trailing area has a
second inclined portion, and wherein, when the high pressure
opening finishes being connected with the opening of one of the
introducing passages, the second inclined portion extends along the
first inclined portion.
8. The compressor according to claim 7, wherein, when the high
pressure opening finishes being connected with the opening of one
of the introducing passages, the entire second inclined portion
overlaps the first inclined portion.
9. The compressor according to claim 8, wherein the each first
inclined portion has a curved portion, and wherein the second
inclined portion conforms to the shape of the curved portions.
10. A piston type compressor comprising: a suction pressure zone,
the internal pressure of which is a suction pressure; a discharge
pressure zone, the internal pressure of which is a discharge
pressure; a rotary shaft; a piston type compression mechanism,
wherein the compression mechanism includes a plurality of cylinders
and pistons, wherein each piston is accommodated in one of the
cylinders, and defines a compression chamber in the associated
cylinder, wherein, as the rotary shaft rotates, each piston draws
gas from the suction pressure zone into the associated compression
chamber, compresses the gas in the compression chamber, and
discharges the gas to the discharge pressure zone; a plurality of
introducing passages, each extending from one of the compression
chambers; and a cylindrical rotary valve located between the
suction pressure zone and the introducing passages, wherein the
rotary valve rotates synchronously with rotation of the rotary
shaft, wherein the rotary valve has a suction communicating passage
and a residual gas bypass passage, wherein, as the rotary shaft
rotates, the suction communicating passage consecutively connects,
through the corresponding introducing passage, the suction pressure
zone with a compression chamber corresponding to a piston in the
suction stroke, and wherein the residual gas bypass passage
connects the introducing passage that extends from one of the
compression chambers in which the discharge stroke has been
finished, or a high pressure introducing passage, with the
introducing passage that extends from one of the compression
chambers the pressure of which is lower than the pressure in the
high pressure introducing passage, wherein each introducing passage
has an opening that faces the outer surface of the rotary valve,
wherein the bypass passage has a high pressure opening, and
wherein, as the rotary valve rotates, the high pressure opening is
consecutively connected with the opening of the high pressure
introducing passage, and wherein the peripheral portion of the
opening of each introducing passage and the peripheral portion of
the high pressure opening each have a conforming portion, wherein,
when the high pressure opening starts or finishes being connected
with the opening of the one of the introducing passages, the
conforming portions conform to each other, and each conforming
portion includes a inclined portion that is inclined relative to an
axial direction and a circumferential direction of the rotary
valve.
11. The compressor according to claim 10, wherein each inclined
portion includes a curved portion.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a piston type compressor.
Specifically, the present invention pertains to a piston type
compressor that has a structure for bypassing residual gas
remaining in a compression chamber of high pressure after
discharging gas to a compression chamber of low pressure.
[0002] A piston type compressor disclosed in, for example, Japanese
Laid-Open Patent Publication No. 6-117366 has a compression
mechanism, which has a plurality of cylinders, and a suction valve
unit. As a rotary shaft rotates, pistons disposed in the respective
cylinders reciprocate. The reciprocal motion of the pistons draws
gas into a compression chamber defined in each cylinder from a
suction pressure zone via the suction valve unit. The drawn gas is
then compressed in the compression chamber and subsequently
discharged from the compression chamber. A communicating passage
extends from each compression chamber. The suction valve unit has a
suction guide hole that sequentially connects communicating
passages to the suction pressure zone in the suction stroke as the
suction valve unit rotates in synchronism with the rotary
shaft.
[0003] FIGS. 6(a) and 6(b) show a rotary valve 100 as a suction
valve unit equipped in the piston type compressor disclosed in the
aforementioned publication. In FIGS. 6(a) and 6(b), the rotary
motion of the rotary valve 100 is developed and expressed as a
linear motion. Also, the rotation of the rotary shaft about the
axis is transformed into the leftward movement (see FIG. 6(b)). A
plurality of introducing passages 101 are provided between the
individual cylinders and the outer surface 100a of the rotary valve
100. Each introducing passage 101 has an opening 104 facing the
outer surface 100a of the rotary valve 100. A residual gas bypass
groove 103 is formed on the outer surface 100a of the rotary valve
100. The residual gas bypass groove 103 connects a high pressure
introducing passage 101A among the introducing passages 101, which
communicates with the high pressure compression chamber after the
discharge stroke ends, to a low pressure introducing passage 101B,
which communicates with the low pressure compression chamber.
[0004] The gas remaining undischarged (residual gas) in each
compression chamber after the discharge stroke ends is sent to the
low pressure compression chamber via the high pressure introducing
passage 101A, the residual gas bypass groove 103 and the low
pressure introducing passage 101B. Accordingly, the reexpansion of
the residual gas in the suction stroke of a compression chamber
becomes smaller, making it possible to surely suck the gas in the
suction pressure zone into the compression chamber. This can
improve the volumetric efficiency of the piston type
compressor.
[0005] As indicated by the two-dot chain lines in FIGS. 6(a) and
6(b), the peripheral portion 106 of the opening 104 has curved
portions 106a curved other than radially outward of the rotary
valve 100 for the sake of convenience of processing the high
pressure and low pressure introducing passages 101A and 101B and
increasing the strengths thereof, and some other reasons.
[0006] In a part of each curved portion 106a that is closer to the
residual gas bypass groove 103, an approximately right quarter
circle portion in FIGS. 6(a) and 6(b) or an advancing area 106a-1
is equivalent to an inclined portion extending in the
circumferential direction (lateral direction in the diagrams) and
the axial direction (vertical direction in the diagrams) of the
rotary valve 100. In the same curved portion 106a, an approximately
left-quarter circle portion in the diagrams or a trailing area
106a-2 is also equivalent to an inclined portion extending in the
circumferential direction and the axial direction of the rotary
valve 100.
[0007] Two openings that communicate with the individual
introducing passages 101 and the opening 104 are formed in the
residual gas bypass groove 103. Each opening has a constant width
extending in the axial direction. Of the two openings, a high
pressure opening 103a located closer to the high pressure
introducing passage 101A has a peripheral portion 105 whose
advancing area 105a and trailing area 105b are formed straight
extending in the axial direction of the rotary valve 100.
[0008] As shown in FIG. 6(a), at the time the communication of the
high pressure opening 103a with the opening 104 of the high
pressure introducing passage 101A starts, the advancing area 105a
of the peripheral portion 105 of the high pressure opening 103a
overlaps a advancing-area 106b-1 of a linear portion 106b of the
peripheral portion 106 of the high pressure introducing passage
101A. In this state, the lower in the diagram downward the
advancing area 105a of the peripheral portion 105 of the high
pressure opening 103a is, the longer the distance from the
advancing area 106a-1 of the curved portion 106a of the peripheral
portion 106 of the high pressure introducing passage 101A
becomes.
[0009] As indicated by the two-dot chain line in FIG. 6(a), even
when the communication of the high pressure opening 103a with the
opening 104 of the high pressure introducing passage 101A starts,
it takes time for the advancing area 105a of the peripheral portion
105 of the high pressure opening 103a to significantly come inside
the advancing area 106a-1 of the curved portion 106a. As a result,
the opening area (overlapping area) of the high pressure opening
103a with respect to the opening 104 of the high pressure
introducing passage 101A increases gently.
[0010] As shown in FIG. 6(b), at the time the communication of the
high pressure opening 103a with the opening 104 of the high
pressure introducing passage 101A ends, the trailing area 105b of
the peripheral portion 105 of the high pressure opening 103a
overlaps a trailing area 106b-2 of the linear portion 106b of the
peripheral portion 106 of the high pressure introducing passage
101A. In this state, the trailing area 105b of the peripheral
portion 105 of the high pressure opening 103a has already passed
the trailing area 106a-2 of the curved portion 106a in the
peripheral portion 106 of the high pressure introducing passage
101A. That is, as indicated by the two-dot chain line in FIG. 6(b),
the opening area of the high pressure opening 103a with respect to
the opening 104 of the high pressure introducing passage 101A is
greatly reduced a long time before the communication of the high
pressure opening 103a with the opening 104 of the high pressure
introducing passage 101A ends.
[0011] To reliably send the residual gas remaining in a compression
chamber of high pressure after discharging gas to a compression
chamber of low pressure, therefore, it is necessary to make the
width of the high pressure opening 103a of the residual gas bypass
groove 103 wider, that is, set the rotation angle of the rotary
valve 100 larger during the period from the beginning of the
communication of the opening 103a with the opening 104 of the
introducing passage 101 till the end of the communication.
[0012] To set the width of the high pressure opening 103a wider,
the advancing area 105a of the peripheral portion 105 of the high
pressure opening 103a may be positioned farther away from an
opening 107a of a suction guide hole 107. In this case, however,
the timing at which communication of the high pressure opening 103a
with the opening 104 of the introducing passage 101 starts is
advanced, leading to early bypassing and recompression of the
dischargeable gas. In the case where the width of the high pressure
opening 103a is set wider, therefore, the trailing area 105b of the
peripheral portion 105 should be positioned closer to the opening
107a of the suction guide hole 107 to delay the timing at which
communication of the high pressure opening 103a with the opening
104 of the introducing passage 101 ends.
[0013] The piston type compressor requires some measures against
prevention of bypassing of the gas between the high pressure
opening 103a of the residual gas bypass groove 103 and the opening
107a of the suction guide hole 107 via the opening 104 of the
introducing passage 101. In other words, in the seal area between
the high pressure opening 103a of the residual gas bypass groove
103 and the opening 107a of the suction guide hole 107 at the outer
surface 100a of the rotary valve 100 needs an area large enough to
block the opening 104 of the introducing passage 101.
[0014] Therefore, widening the high pressure opening 103a to delay
the timing at which communication of the high pressure opening 103a
with the opening 104 of the introducing passage 101 ends leads to
the delayed starting (delayed suction) of communication of the
introducing passage 101 with the suction guide hole 107. This
reduces the effect of an improvement on the volumetric efficiency
brought about by collecting the residual gas.
SUMMARY OF THE INVENTION
[0015] Accordingly, it is an objective of the present invention to
provide a piston type compressor capable of promptly blocking
communication of the high pressure opening of a residual gas bypass
groove with an opening of a communicating passage while keeping a
sufficient volumetric efficiency, thereby quickly starting the
suction stroke.
[0016] To achieve the above objects, the present invention provides
a piston type compressor including a suction pressure zone, a
discharge pressure zone, a rotary shaft, a piston type compression
mechanism, a plurality of introducing passages and a cylindrical
rotary valve. The internal pressure of suction pressure zone is a
suction pressure. The internal pressure of the discharge pressure
zone is a discharge pressure. The compression mechanism includes a
plurality of cylinders and pistons. Each piston is accommodated in
one of the cylinders, and defines a compression chamber in the
associated cylinder. As the rotary shaft rotates, each piston draws
gas from the suction pressure zone into the associated compression
chamber, compresses the gas in the compression chamber, and
discharges the gas to the discharge pressure zone. Each introducing
passage extends from one of the compression chambers. The
cylindrical rotary valve is located between the suction pressure
zone and the introducing passages. The rotary valve rotates
synchronously with rotation of the rotary shaft. The rotary valve
has a suction communicating passage and a residual gas bypass
passage. As the rotary shaft rotates, the suction communicating
passage consecutively connects, through the corresponding
introducing passage, the suction pressure zone with a compression
chamber corresponding to a piston in the suction stroke. The
residual gas bypass passage connects the introducing passage that
extends from one of the compression chambers in which the discharge
stroke has been finished, or a high pressure introducing passage,
with the introducing passage that extends from one of the
compression chambers the pressure of which is lower than the
pressure in the high pressure introducing passage. Each introducing
passage has an opening that faces the outer surface of the rotary
valve. The bypass passage has a high pressure opening. As the
rotary valve rotates, the high pressure opening is consecutively
connected with the opening of the high pressure introducing
passage. A peripheral portion of the opening of each introducing
passage has a first advancing area. When the high pressure opening
starts being connected with the opening of the introducing passage,
the first advancing area overlaps the high pressure opening. The
first advancing area has a first inclined portion that is inclined
relative to an axial direction and a circumferential direction of
the rotary valve. A peripheral portion of the high pressure opening
has a second advancing area. When the high pressure opening starts
being connected with the opening of one of the introducing
passages, the second advancing area overlaps the opening of the
introducing passage. The second advancing area has a second
inclined portion. When the high pressure opening starts being
connected with the opening of one of the introducing passages, the
second inclined portion extends along the first inclined
portion.
[0017] The present invention also provides a piston type compressor
including a suction pressure zone, a discharge pressure zone, a
rotary shaft, a piston type compression mechanism, a plurality of
introducing passage, and a cylindrical rotary valve. The internal
pressure of the suction pressure zone is a suction pressure. The
internal pressure of the discharge pressure zone is a discharge
pressure. The compression mechanism includes a plurality of
cylinders and pistons. Each piston is accommodated in one of the
cylinders, and defines a compression chamber in the associated
cylinder. As the rotary shaft rotates, each piston draws gas from
the suction pressure zone into the associated compression chamber,
compresses the gas in the compression chamber, and discharges the
gas to the discharge pressure zone. Each introducing passage
extends from one of the compression chambers. The cylindrical
rotary valve is located between the suction pressure zone and the
introducing passages. The rotary valve rotates synchronously with
rotation of the rotary shaft. The rotary valve has a suction
communicating passage and a residual gas bypass passage. As the
rotary shaft rotates, the suction communicating passage
consecutively connects, through the corresponding introducing
passage, the suction pressure zone with a compression chamber
corresponding to a piston in the suction stroke. The residual gas
bypass passage connects the introducing passage that extends from
one of the compression chambers in which the discharge stroke has
been finished, or a high pressure introducing passage, with the
introducing passage that extends from one of the compression
chambers the pressure of which is lower than the pressure in the
high pressure introducing passage. Each introducing passage has an
opening that faces the outer surface of the rotary valve. The
bypass passage has a high pressure opening. As the rotary valve
rotates, the high pressure opening is consecutively connected with
the opening of the high pressure introducing passage. A peripheral
portion of the opening of each introducing passage has a first
trailing area. When the high pressure opening finishes being
connected with the opening of the introducing passage, the high
pressure opening passes over the first trailing area. The first
trailing area has a first inclined portion that is inclined
relative to an axial direction and a circumferential direction of
the rotary valve. A peripheral portion of the high pressure opening
has a second trailing area. When the high pressure opening finishes
being connected with the opening of one of the introducing
passages, the second trailing area passes over the opening of the
introducing passage. The second trailing area has a second inclined
portion. When the high pressure opening finishes being connected
with the opening of one of the introducing passages, the second
inclined portion extends along the first inclined portion.
[0018] Other aspects and advantages of the invention will become
apparent from the following description, taken in conjunction with
the accompanying drawings, illustrating by way of example the
principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The invention, together with objects and advantages thereof,
may best be understood by reference to the following description of
the presently preferred embodiments together with the accompanying
drawings in which:
[0020] FIG. 1 is a cross-sectional view of a variable displacement
swash plate type compressor according to a first embodiment of the
present invention;
[0021] FIG. 2 is a cross-sectional view taken along line 2-2 in
FIG. 1;
[0022] FIG. 3(a) is a linearly developed diagram showing the rotary
motion of the rotary valve of the compressor in FIG. 1;
[0023] FIG. 3(b) is another linearly developed diagram showing the
rotary motion of the rotary valve of the compressor in FIG. 1;
[0024] FIG. 4 is a developed diagram of a rotary valve according to
a modified embodiment;
[0025] FIG. 5 is a developed diagram of a rotary valve according to
another modified embodiment;
[0026] FIG. 6(a) is a developed diagram showing a prior art rotary
valve; and
[0027] FIG. 6(b) is another developed diagram of the rotary valve
in FIG. 6(a).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] A piston type compressor according to one embodiment of the
present invention will now be described. In this embodiment, the
piston type compressor is a variable displacement swash plate type
compressor for compressing a refrigerant, which used in a vehicular
air-conditioning system.
[0029] As shown in FIG. 1, a variable displacement swash plate type
compressor 10 has a cylinder block 11, a front housing member 12
securely connected to the front end of the cylinder block 11, and a
rear housing member 13 securely connected to the rear end of the
cylinder block 11 via a valve plate 13. The cylinder block 11, the
front housing member 12 and the rear housing member 14 constitute
the housing of the compressor 10. The leftward in FIG. 1 is the
frontward of the compressor 10 and the rightward is the rearward
thereof.
[0030] A crank chamber 15 is defined in an area surrounded by the
cylinder block 11 and the front housing member 12. A rotary shaft
16 is placed so as to extend through the crank chamber 15 and is
rotatably supported between the front housing member 12 and the
cylinder block 11. The rotary shaft 16 is coupled to an engine Eg
as the drive source for a vehicle and rotates with the power
supplied from the engine Eg.
[0031] A lug plate 20 is fixed to the rotary shaft 16 in the crank
chamber 15 in such a way as to be rotatable with the rotary shaft
16. A swash plate 21 as a driving member is retained in the crank
chamber 15. The swash plate 21 is supported on the rotary shaft 16
in such a way as to be slidable and tiltable. A hinge mechanism 22
intervenes between the lug plate 20 and the swash plate 21. Being
hinged to the lug plate 20 via the hinge mechanism 22 and supported
on the rotary shaft 16, therefore, the swash plate 21 is rotatable
in synchronism with the lug plate 20 and the rotary shaft 16 and
tiltable with respect to the rotary shaft 16 while sliding in the
direction of an axis L of the rotary shaft 16.
[0032] The compressor 10 has a compression mechanism with plural
(five in this embodiment) cylinders. That is, a plurality of
cylinder bores 23 (only one shown in FIG. 1) are bored through the
cylinder block 11 in such a way as to surround the rear end side of
the rotary shaft 16 at equal angular intervals, as shown in FIGS. 1
and 2. Single-headed pistons 24 are retained in the respective
cylinder bores 23 in a reciprocal manner.
[0033] The front and rear openings of the cylinder bore 23 are
blocked by the valve plate 13 and the piston 24. Defined in the
cylinder bore 23 is a compression chamber 26 whose volume varies
with the reciprocation of the piston 24 in the cylinder bore 23.
Each piston 24 is engaged to the outer peripheral portion of the
swash plate 21 via shoes 25. Therefore, the rotation of the swash
plate 21 with the rotation of the rotary shaft 16 is converted to
the reciprocal motion of the piston 24 via the shoes 25.
[0034] A suction passage 27 as a suction pressure zone and a
discharge chamber 28 as a discharge pressure zone are defined in
the rear housing member 14. The suction passage 27 is formed in the
center portion of the rear housing member 14. The discharge chamber
28 is formed in such a way as to surround the outer surface of the
suction passage 27. An external pipe, which connects to a low
pressure heat exchanger of an unillustrated external refrigerant
circuit, is connected to the suction passage 27. An external pipe,
which connects to a high pressure heat exchanger of the
unillustrated external refrigerant circuit, is connected to the
discharge chamber 28. The external refrigerant circuit and the
compressor 10 constitute a refrigerant circulation circuit.
[0035] As each piston 24 moves from the top dead center to the
bottom dead center, the refrigerant gas in the suction passage 27
is sucked into the compression chamber 26 via a suction valve unit
55 disposed in the cylinder block 11. As the piston 24 moves from
the bottom dead center to the top dead center, the refrigerant gas
sucked in the compression chamber 26 is compressed to a
predetermined pressure and is discharged into the discharge chamber
28 via a discharge port 29 formed in the valve plate 13 and a
discharge valve 30.
[0036] A bleed passage 31, a supply passage 32 and a control valve
33 are provided in the housing of the compressor 10. The bleed
passage 31 includes an axial passage 34 formed in the axial center
of the rotary shaft 16. The axial passage 34 has an inlet 34a open
to the crank chamber 15 near the lug plate 20 and an outlet 34b
open at the rear end of the rotary shaft 16. The supply passage 32
connects the discharge chamber 28 to the crank chamber 15. The
well-known control valve 33 comprised of an electromagnetic valve
is disposed in the midway of the supply passage 32.
[0037] By adjusting the degree of opening of the control valve 33,
the balance between the amount of the high pressure discharge gas
led into the crank chamber 15 via the supply passage 32 and the
amount of the gas led out of the crank chamber 15 via the bleed
passage 31 is controlled to determine the pressure in the crank
chamber 15. In accordance with a change in the pressure in the
crank chamber 15, the difference between the pressure in the crank
chamber 15 and the pressure in compression chamber 26 via the
piston 24 is changed, thereby altering the tilt angle of the swash
plate 21. As a result, the stroke of the piston 24, i.e., the
displacement of the compressor 10 is adjusted.
[0038] As the pressure in the crank chamber 15 drops, for example,
the tilt angle of the swash plate 21 increases and the stroke of
the piston 24 increases, thereby making the displacement of the
compressor 10 larger. As the pressure in the crank chamber 15
rises, on the other hand, the tilt angle of the swash plate 21
decreases and the stroke of the piston 24 decreases, thereby making
the displacement of the compressor 10 smaller.
[0039] The suction valve unit 55 is discussed below.
[0040] As shown in FIGS. 1 and 2, a cylindrical holding bore 17 is
formed in the center portion of the cylinder block 11 and
surrounded by the cylinder bores 23 in the housing of the
compressor 10. A through hole 13a that connects the holding bore 17
to the suction passage 27 is bored through the valve plate 13.
Plural (five in this embodiment) introducing passages 18 laid out
in the cylinder block 11 at predetermined angular distances about
the axis L are provided between the holding bore 17 and the
individual compression chambers 26. Each introducing passage 18
connects the holding bore 17 to the associated compression chamber
26.
[0041] A bottomed cylindrical rotary valve 35 having a bottom
frontward is rotatably retained in the holding bore 17. An inner
surface 17a of the holding bore 17 is slidably in contact with an
outer surface 35b of the rotary valve 35. A communicating hole 35c
extending along the direction of the axis L is bored through at the
front side of the rotary valve 35. A suction chamber 36 that is the
cylindrical space in the rotary valve 35 communicates with the
axial passage 34 (outlet 34b) of the rotary shaft 16 via the
communicating hole 35c. The communicating hole 35c is a part of the
bleed passage 31 and the suction chamber 36 is the suction pressure
zone to which the bleed passage 31 is connected. The bleed passage
31 connects the crank chamber 15 to the suction chamber 36.
[0042] The rotary valve 35 has a small-diameter portion 35a that is
smaller in diameter than the other portion. An attachment hole 16a
is provided at the rear end portion of the rotary shaft 16. The
small-diameter portion 35a of the rotary valve 35 is securely
fitted with pressure in the attachment hole 16a of the rotary shaft
16. Accordingly, the rotary shaft 16 and the rotary valve 35 are
laid out on the same axis L and integrated, so that the rotary
valve 35 rotates in synchronism with the rotation of the rotary
shaft 16 or the reciprocation of the piston 24. The outer surface
35b of the rotary valve 35 and the inner surface 17a of the holding
bore 17 constitute a slide bearing surface that supports the rear
end portion of the rotary shaft 16 in a rotatable manner.
[0043] The suction chamber 36 of the rotary valve 35 communicates
with the suction passage 27 via the through hole 13a of the valve
plate 13. A suction guide hole 37 that is normally connected to the
suction chamber 36 is formed in a given circumferential zone in the
wall of the rotary valve 35. The suction guide hole 37 serves as a
suction communicating passage that sequentially connects the
suction chamber 36 as the suction pressure zone to the introducing
passages 18 extending from the individual compression chambers 26
in synchronism with the rotation of the rotary valve 35.
[0044] In the case where the piston 24 moves from the top dead
center to the bottom dead center (suction stroke), the suction
guide hole 37 communicates with the introducing passage 18 of the
cylinder block 11. The refrigerant gas in the suction passage 27 is
sucked into the compression chamber 26, passing the suction chamber
36 of the rotary valve 35, the suction guide hole 37 and the
introducing passage 18 in the named order.
[0045] When the piston 24 reaches the bottom dead center, the
suction guide hole 37 is completely deviated circumferentially from
the introducing passage 18, so that suction of the refrigerant gas
into the compression chamber 26 from the suction chamber 36 is
stopped. As the piston 24 moves toward the top dead center
(compression/discharge stroke), the seal area of the outer surface
35b of the rotary valve 35 keeps the space between the introducing
passage 18 and the suction chamber 36 blocked, so that the
compression of the refrigerant gas and the discharge of the
compressed gas into the discharge chamber 28 are not
interfered.
[0046] The following discusses the residual gas bypass
structure.
[0047] FIGS. 3(a) and 3(b) illustrate a state where the rotary
motion of the rotary valve 35 is developed linearly and the
rotation of the rotary valve 35 about the axis L of the rotary
valve 35 is transformed to the leftward movement. A residual gas
bypass groove 41 as residual gas bypass passage is formed in the
seal area at the outer surface 35b of the rotary valve 35.
[0048] The residual gas bypass groove 41 includes a high pressure
groove 42 as a high pressure opening extending along the axis L of
the rotary valve 35, a low pressure groove 43 likewise extending
along the axis L and a communicating groove 44 that extends along
the circumferential direction (lateral direction in the diagrams)
of the rotary valve 35 and connects the front ends of both grooves
42 and 43. The residual gas bypass groove 41 connects a high
pressure introducing passage 18A among the plural introducing
passages 18 that communicates with the high pressure compression
chamber 26 in which the discharge stroke has been finished with a
low pressure introducing passage 18B that extends from the
compression chamber 26 the pressure of which is lower than the
pressure in the compression chamber 26 in which the discharge
stroke has been finished (the high pressure introducing passage
18A).
[0049] The high pressure groove 42 is located in the outer surface
35b of the rotary valve 35 at the seal area facing the high
pressure introducing passage 18A. The low pressure groove 43 is
located in the outer surface 35b of the rotary valve 35 at the seal
area facing the low pressure introducing passage 18B. The timing at
which communication of the low pressure groove 43 with the low
pressure introducing passage 18B starts is set slightly earlier
than the timing at which communication of the high pressure groove
42 with the high pressure introducing passage 18A starts.
[0050] The refrigerant gas (residual gas) remaining undischarged in
the compression chamber 26 immediately after the end of the
discharge stroke is bypassed (collected into) to the low pressure
compression chamber 26 immediately after the end of the suction
stroke, passing the high pressure introducing passage 18A, the high
pressure groove 42, the communicating groove 44., the low pressure
groove 43 and the low pressure introducing passage 18B in order.
This makes re-expansion of the residual gas bypass in the suction
stroke of the compression chamber 26 less, so that the refrigerant
gas in the suction chamber 36 is reliably led into the compression
chamber 26, thereby improving the volumetric efficiency of the
compressor 10.
[0051] As indicated by the two-dot chain lines in FIGS. 3(a) and
3(b), each introducing passage 18 provided in the cylinder block 11
has an opening 51 facing the outer surface 35b of the rotary valve
35. For the sake of convenience of ensure the strength of the
cylinder block 11 or some other reasons, a peripheral portion 52 of
the opening 51 of each introducing passage 18 has curved portions
52b curved in other directions than the radially outward direction
of the rotary valve 35. That is, as seen from the developed view of
the inner surface 17a of the holding bore 17, the peripheral
portion 52 of the opening 51 includes a linear portion 52a of a
given width extending along the axis L and the curved portions 52b
formed at both ends of the linear portion 52a and having an
approximately semicircular shape. The curved portion 52b functions
as a first advanced area.
[0052] The right-hand straight part of the linear portion 52a of
the peripheral portion 52 in the diagrams is a advancing area 52a-1
and the left-hand straight part of the linear portion 52a is a
trailing area 52a-2. In the curved portion 52b positioned closer to
the communicating groove 44, an approximately right quarter circle
portion in the diagrams is an advancing area 52b-1 and an
approximately left quarter circle portion in the diagrams is a
trailing area 52b-2.
[0053] In this embodiment, a part of the advancing area 52a-1 of
the linear portion 52a and the advancing area 52b-1 of the curved
portion 52b constitute the "first advancing area" in the peripheral
portion 52 of the opening 51 of the introducing passage 18. In this
embodiment, a part of the trailing area 52a-2 of the linear portion
52a and the trailing area 52b-2 of the curved portion 52b
constitute the "first trailing area" in the peripheral portion 52
of the opening 51 of the introducing passage 18.
[0054] The advancing area 52b-1 and the trailing area 52b-2 of the
curved portion 52b extend in the circumferential direction and the
direction of the axis L of the rotary valve 35, respectively. In
this embodiment, the advancing area 52b-1 and trailing area 52b-2
of the curved portion 52b are respectively equivalent to inclined
portions.
[0055] As seen from the developed view of the outer surface 35b of
the rotary valve 35, the high pressure groove 42 of the residual
gas bypass groove 41 has a proximal portion 42a of a given width
extending rearward in the direction of the axis L from the
communicating groove 44 and a distal portion 42b extending rearward
in the direction of the axis L from the proximal portion 42a and
having a crest-like shape with the proximal portion 42a as the foot
side.
[0056] With the distal portion 42b, the high pressure groove 42 can
communicate with the opening 51 of the introducing passage 18. A
peripheral portion 45 of the distal portion 42b in the high
pressure groove 42 includes a curved portion 45a on that side of
the proximal portion 42a and a linear portion 45b of a given width
on the distal end side.
[0057] In the peripheral portion 45 of the distal portion 42b of
the high pressure groove 42, that straight part of the linear
portion 45b that is far from an opening 37a of the suction guide
hole 37 is an advancing area 45b-1 and that straight part of the
linear portion 45b that is close to the opening 37a of the suction
guide hole 37 is a trailing area 45b-2. In the peripheral portion
45 of the distal portion 42b of the high pressure groove 42, an
approximately quarter circle portion on the far side from the
opening 37a of the suction guide hole 37 is a advancing area 45a-1
and an approximately left quarter circle portion on the side close
to the opening 37a of the suction guide hole 37 is a trailing area
45a-2.
[0058] In this embodiment, the advancing area 45b-1 of the linear
portion 45b and the advancing area 45a-1 of the curved portion 45a
constitute the "second advancing area" in the peripheral portion 45
of the high pressure groove 42. In this embodiment, the trailing
area 45b-2 of the linear portion 45b and the trailing area 45a-2 of
the curved portion 45a constitute the "second trailing area" in the
peripheral portion 45 of the high pressure groove 42.
[0059] The individual areas 45a-1 and 45a-2 of the curved portion
45a are curved inward of the high pressure groove 42. The figure of
the advancing area 45a-1 is congruous with the figure of the
advancing area 52b-1 of the curved portion 52b of the opening 51.
The figure of the trailing area 45a-2 is congruous with the figure
of the trailing area 52b-2 of the curved portion 52b of the
peripheral portion 52.
[0060] As shown in FIG. 3(a), the entire advancing area 45b-1 of
the linear portion 45b of the peripheral portion 45 of the distal
portion 42b in the high pressure groove 42 overlaps a part of the
advancing area 52a-1 of the linear portion 52a of the peripheral
portion 52 at the time communication of the peripheral portion 45
with the opening 51 of the introducing passage 18A starts. Further,
the entire advancing area 45a-1 of the curved portion 45a of the
peripheral portion 45 of the distal portion 42b in the high
pressure groove 42 overlaps the advancing area 52b-1 of the curved
portion 52b of the peripheral portion 52 at the time communication
of the peripheral portion 45 with the opening 51 of the introducing
passage 18A starts.
[0061] That is, in this embodiment, the advancing area 45a-1 of the
curved portion 45a at the peripheral portion 45 of the high
pressure groove 42 can be grasped as a "inclined portion that can
extend along the inclined portion of the peripheral portion at the
opening of the communicating passage at the beginning of
communication with the opening of the communicating passage".
[0062] As shown in FIG. 3(b), the entire trailing area 45b-2 of the
linear portion 45b of the peripheral portion 45 of the distal
portion 42b in the high pressure groove 42 overlaps a part of the
trailing area 52a-2 of the linear portion 52a of the peripheral
portion 52 at the time communication of the peripheral portion 45
with the opening 51 of the introducing passage 18A ends. Further,
the entire trailing area 45a-2 of the curved portion 45a of the
peripheral portion 45 of the distal portion 42b in the high
pressure groove 42 overlaps the trailing area 52b-2 of the curved
portion 52b of the peripheral portion 52 at the time communication
of the peripheral portion 45 with the opening 51 of the introducing
passage 18A ends.
[0063] That is, in this embodiment, the trailing area 45a-2 of the
curved portion 45a at the peripheral portion 45 of the high
pressure groove 42 can be grasped as a "inclined portion that can
extend along the inclined portion of the peripheral portion at the
opening of the communicating passage at the end of communication
with the opening of the communicating passage".
[0064] The embodiment with the above-described structure has the
following advantages.
[0065] An inclined portion (advancing area 45a-1) that can extend
along the inclined portion (advancing area 52b-1) of the peripheral
portion 52 at the beginning of communication with the opening 51 of
the high pressure introducing passage 18A is formed in the
advancing area 45a-1, 45b-1 of the peripheral portion 45 in the
high pressure groove 42.
[0066] When communication with the high pressure introducing
passage 18A starts, as indicated by the two-dot chain line in FIG.
3(a), the advancing area 45a-1 of the curved portion 45a at the
opening's peripheral portion 45 of the high pressure groove 42
quickly passes through the advancing area 52b-1 of the curved
portion 52b of the peripheral portion 52. Therefore, the opening
area (overlapping area) with respect to the opening 51 of the
introducing passage 18A is increased rapidly.
[0067] Consequently, even with the quickened timing of ending
communication with the opening 51 of the high pressure introducing
passage 18A and the high pressure groove 42, the residual gas in
the compression chamber 26 is reliably bypassed, and eventually the
timing of starting communication of the high pressure introducing
passage 18A with the suction guide hole 37 can be advanced. In
other words, this embodiment can effectively use the advancing area
52b-1, 52b-2 of the curved portion 52b in the opening 51 of the
high pressure introducing passage 18A as the portion where the
residual gas passes immediately after the beginning of the
communication with the high pressure groove 42.
[0068] Particularly, this embodiment is designed in such a way that
the entire advancing area 45a-1 of the high pressure groove 42
overlaps the advancing area 52b-1 of the high pressure introducing
passage 18A at the time communication of the high pressure groove
42 with the opening 51 of the introducing passage 18A starts.
Therefore, the aforementioned advantage works more effectively.
[0069] An inclined portion (trailing area 45a-2) that can extend
along the inclined portion (trailing area 52b-2) of the peripheral
portion 52 at the end of communication with the opening 51 of the
introducing passage 18A is formed in the trailing area 45a-2, 45b-2
of the peripheral portion 45 in the high pressure groove 42.
[0070] Therefore, as shown in FIG. 3(b), the trailing area 45a-2 of
the curved portion 45a at the opening's peripheral portion 45 of
the high pressure groove 42 does not suddenly pass through the
trailing area 52b-2 of the curved portion 52b of the peripheral
portion 52 until the end of the communication of the high pressure
groove 42 with the opening 51 of the high pressure introducing
passage 18A. As indicated by the two-dot chain line in FIG. 3B,
therefore, the opening area with respect to the opening 51 of the
introducing passage 18A in the high pressure groove 42 can be kept
greatly until immediately before the end of the communication of
the high pressure groove 42 with the opening 51 of the high
pressure introducing passage 18A.
[0071] As a result, even with the quickened timing of ending
communication of the high pressure groove 42 with the opening 51 of
the high pressure introducing passage 18A, the residual gas in the
compression chamber 26 is reliably bypassed, and eventually the
timing of starting communication of the high pressure introducing
passage 18A with the suction guide hole 37 of the introducing
passage 18A can be advanced. In other words, this embodiment
effectively uses the advancing area 52b-1, 52b-2 of the curved
portion 52b in the opening 51 of the high pressure introducing
passage 18A as the portion where the residual gas passes until
immediately before the end of the communication with the high
pressure groove 42.
[0072] Particularly, this embodiment is designed in such a way that
the entire trailing area 45a-2 of the high pressure groove 42
overlaps the trailing area 52b-2 of the high pressure introducing
passage 18A at the time communication of the high pressure groove
42 with the opening 51 of the introducing passage 18 ends.
Therefore, the aforementioned advantage works more effectively.
[0073] It should be apparent to those skilled in the art that the
present invention may be embodied in many other specific forms
without departing from the spirit or scope of the invention.
Particularly, it should be understood that the invention may be
embodied in the following forms.
[0074] As shown in FIG. 4, the peripheral portion 45 of the high
pressure groove 42 may be constructed in such a way that only the
advancing area 45a-1 of the curved portion 45a extends along the
advancing area 52b-1 of the curved portions 52b of the peripheral
portion 52 of the high pressure introducing passage 18A at the
beginning of the communication of the high pressure groove 42 with
the opening 51 of the high pressure introducing passage 18A. In
this case, the trailing area 45b-2 of the linear portion 45b
extends linearly to the communicating groove 44.
[0075] This embodiment has advantages similar to those of the
embodiment in FIGS. 1 to 3(b).
[0076] As shown in FIG. 5, the peripheral portion 45 of the high
pressure groove 42 may be constructed in such a way that only the
trailing area 45a-2 of the curved portion 45a extends along the
trailing area 52b-2 of the curved portions 52b of the peripheral
portion 52 of the high pressure introducing passage 18A at the end
of the communication of the high pressure groove 42 with the
opening 51 of the high pressure introducing passage 18A. In this
case, the advancing area 45b-1 of the linear portion 45b extends
linearly to the communicating groove 44. This embodiment also has
advantages similar to those of the embodiment in FIGS. 1 to
3(b).
[0077] In the embodiments in FIGS. 1 to 3(b) and FIG. 4, extension
of the advancing area 45a-1 of the high pressure groove 42 along
the advancing area 52b-1 of the high pressure introducing passage
18A is not limited to the entire advancing area 45a-1 overlapping
the advancing area 52b-1.
[0078] That is, the advancing area 45a-1 of the high pressure
groove 42 and the advancing area 52b-1 of the high pressure
introducing passage 18A may be laid out slightly deviated from each
other along the direction of the axis L. Alternatively, in the
embodiments in FIGS. 1 to 3(b) and FIG. 4, for example, the degree
of curvature of the advancing area 45a-1 of the high pressure
groove 42 may be made slightly different from the degree of
curvature of the advancing area 52b-1 of the high pressure
introducing passage 18A.
[0079] In the embodiments in FIGS. 1 to 3(b) and FIG. 5, extension
of the trailing area 45a-2 of the high pressure groove 42 along the
trailing area 52b-2 of the high pressure introducing passage 18A is
not limited to the entire trailing area 45a-2 overlapping the
trailing area 52b-2.
[0080] That is, the trailing area 45a-2 of the high pressure groove
42 and the trailing area 52b-2 of the high pressure introducing
passage 18A may be laid out slightly deviated from each other along
the direction of the axis L. Alternatively, in the embodiments
(FIGS. 1 to 3(b) and FIG. 5), for example, the degree of curvature
of the trailing area 45a-2 of the high pressure groove 42 may be
made slightly different from the degree of curvature of the
trailing area 52b-2 of the high pressure introducing passage
18A.
[0081] In the embodiments in FIGS. 1 to 3(b) and FIG. 5, the linear
portion 45b (advancing area 45b-1 and trailing area 45b-2) may be
omitted from the high pressure groove 42.
[0082] In the embodiments in FIGS. 1 to 5, as seen from the
developed view of the inner surface 17a of the holding bore 17, the
peripheral portion 52 of the introducing passage 18 has the curved
portions 52b (inclined portions 52b-1, 52b-2) curved in the
direction of the axis L. However, the shapes of the inclined
portions are not limited to the curved shape in the state where the
holding bore 17 is developed. That is, the inclined portions may
have a linear shape in the state where the holding bore 17 is
developed, as long as the condition that the inclined portions
extend in the circumferential direction of the rotary valve 35 and
the direction of the axis thereof is satisfied. In this case, the
advancing areas 45a-1, 45a-2 of the high pressure groove 42 are
designed to have a linear shape in the state where the outer
surface 35b of the rotary valve 35 is developed.
[0083] The invention may be adapted to a wobble type variable
displacement compressor.
[0084] The invention may be adapted to a double-headed piston type
compressor.
[0085] The invention may be adapted to a piston type compressor 10
that uses a wave cam, in place of the swash plate 21, as a driving
member.
[0086] The present examples and embodiments are to be considered as
illustrative and not restrictive and the invention is not to be
limited to the details given herein, but may be modified within the
scope and equivalence of the appended claims.
* * * * *